Transfer sheet

ABSTRACT

The invention relates to a transfer sheet suitable for the formation of electrode patterns, dielectric layers, barrier layers, etc. in plasma display panels (PDPs), field emission displays (FEDS), liquid crystal displays (LCDs), fluorescent displays, hybrid integrated circuits, etc. The transfer sheet comprises a base film and a transfer layer releasably provided on the base film, optionally with a protective film provided on the transfer layer. The transfer layer comprises an inorganic component including a glass frit and an organic component removable by firing, optionally with an electrically conductive powder. By specifying the surface roughness and surface gloss of the transfer layer, the releasability of the transfer layer with respect to the base or protective film, and the residual solvent content of the transfer layer, it is possible to form, with high accuracy, primer layers, dielectric layers on front or back panel plates, photosensitive black matrix layers, and photosensitive rib layers for use with PDPS, and form high-definition electrode patterns as well.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a transfer sheet suitable forthe formation, with high precision and ease, of electrode patterns,dielectric layers, barrier layers, etc. for use with plasma displaypanels (PDPs), field emission displays (FEDs), liquid crystal displays(LCDs), fluorescent displays, hybrid integrated circuits, etc.

[0002] For fine patterns such as electrodes, dielectric layers, barrierlayers, etc. for use with PDPs, it is now required that they befabricated at low fabrication costs while thickness accuracy and patternaccuracy are maintained at high levels.

[0003] So far, patterns for use with PDPs have been provided by forminga patterning paste having desired properties into a given pattern by aprinting process such as screen or offset printing, followed by drying,and firing. This printing process involves simple steps, and so isexpected to lead to production cost reductions. However, problems withthe screen printing process are that the elongation of a mesh materialforming a screen printing plate places some limitation on printingaccuracy, and that the edge accuracy of the resultant pattern becomeslow due to the occurrence of meshes in the pattern or the spreading ofthe pattern. A problem with the offset printing process is, on the otherhand, that thickness accuracy and pattern accuracy decrease withincreasing printing cycles because some patterning paste is notperfectly transferred to a substrate and so remains on a blanket. It isconsequently required to make frequent blanket replacements, therebypreventing the paste from remaining on the blanket and maintaining theaccuracy of the pattern upon forming. The operation to this end is,however, very troublesome.

[0004] A given thick-film pattern having a high aspect ratio, e.g., aPDP barrier pattern, has so far been formed by a screen printingprocess. With the screen printing process, the limitation of filmthickness formed in one single cycle is of the order of a few tens μm.In other words, printing and drying cycles should be repeated manytimes, generally 10 or more times. A coating film formed by the screenprinting process is generally of a convex shape in section or is bulgingout. Consequently, when a multiplicity of printing cycles are carriedout as mentioned above, coating solution sags are built up at theperiphery of the pattern, and so make the pattern have a spreadingbottom.

[0005] It has recently been proposed to form a barrier layer using atransfer sheet comprising a glass paste provided on a base film (JP-A8-273536). This process makes use of the transfer sheet having a glasspaste layer, and is advantageous in that the process of fabricatingbarriers for PDP panels can be simplified. However, problems arise inconnection with the trapping of air bubbles by transfer, and thereleasability of the glass paste layer from the base film. Especiallywhen a fine electrode pattern or dielectric layer is formed by use ofthe transfer sheet, air bubbles, etc. are likely to pass into thetransfer layer. Also, poor transfer causes breaks in the electrodepattern or pinholes in the dielectric layer.

[0006] In view of such problems as mentioned above, one object of theinvention is to provide a transfer sheet which can be used to form, withgreat accuracy, fine patterns such as electrodes, resistors, e.g.,dielectric layers, barriers, etc. for use image displays such as PDPsand LCDs, thermal heads, integrated circuits, etc.

[0007] Another object of the invention is to provide a transfer sheetwhich can be used to form, with great accuracy, primer layers,dielectric layers on front and back panels, photosensitive black matrixlayers, and photosensitive rib layers for use with PDPs in particular.

[0008] Yet another object of the invention is to provide a transfersheet which makes it possible to form a high-definition electrodepattern.

SUMMARY OF THE INVENTION

[0009] According to the first aspect of the invention, there is provideda transfer sheet comprising, at least, a base film and a transfer layerreleasably provided on the base film, characterized in that the transferlayer comprises, at least, an inorganic component including a glass fritand an organic component removable by firing, and has a surfaceroughness Ra of at most 0.4 μm.

[0010] Preferably, the transfer layer is characterized by having areleasable protective film thereon, and in that the surface roughness Raof the transfer layer upon the protective film released therefrom is atmost 0.2 μm.

[0011] Preferably, the organic component is characterized by beingsensitive to light.

[0012] Preferably, the transfer layer contains a conductive powder asthe inorganic component.

[0013] The first transfer sheet of the invention comprises, at least, abase film and a transfer layer releasably provided on the base film,which transfer layer comprises, at least, an inorganic componentincluding a glass frit and an organic component removable by firing andhas a surface roughness Ra of at most 0.4 μm (the surface roughness Raof the transfer layer upon release of a protective film is at most 0.2μm). Thus, the transfer layer is improved in terms of surfacesmoothness; that is, it is substantially free of defects such asagglomerates, pinholes, etc. due to poor dispersion of the inorganiccomponent. When the transfer layer has a protective film thereon, airbubbles are unlikely to be trapped between the transfer layer and theprotective film, so that the surface smoothness of the transfer layercan be kept in good condition with an improvement in the transferabilityof the transfer layer to an associated application member. It is thuspossible to form a primer or dielectric layer of uniform thickness. Whenthe organic component is sensitive to light, the accuracy of patterningby exposure and development is so improved that high-definition patternsfor electrodes, dielectric layers, etc., and high-definition thick-filmpatterns for barriers, etc. can be formed.

[0014] A second transfer sheet of the invention comprises, at least, abase film and a transfer layer releasably provided on the base film, andis characterized in that the transfer layer comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and has a surface gloss of 20 to 110.

[0015] Preferably, the transfer layer is characterized by having areleasable protective film thereon, and in that the surface gloss of thetransfer layer upon release of the protective film therefrom is in arange of 30 to 110.

[0016] Preferably, the organic component is characterized by beingsensitive to light.

[0017] The second transfer sheet of the invention comprises, at last, abase film and a transfer layer releasably provided on the base film,which transfer layer comprises, at least, an inorganic componentcontaining glass frit and an organic component removable by firing, andhas a surface gloss of 20 to 110 (the surface gloss of the transferlayer upon release of a protective film therefrom is in a range of 30 to110). Thus, the transfer layer is improved in terms of surfacesmoothness; that is, it is substantially free of defects such asagglomerates, pinholes, etc. due to poor dispersion of the inorganiccomponent. When the transfer layer has a protective film thereon, airbubbles are unlikely to be trapped between the transfer layer and theprotective film, so that the surface smoothness of the transfer layercan be kept in good condition with an improvement in the transferabilityof the transfer layer to an associated application member. It is thuspossible to form a primer or dielectric layer of uniform thickness. Whenthe organic component is sensitive to light, the accuracy of patterningby exposure and development is so improved that high-definition patternsfor electrodes, dielectric layers, etc., and high-definition thick-filmpatterns for barriers, etc. can be formed.

[0018] A third transfer sheet of the invention comprises, at least, abase film and a transfer sheet releasably provided on the base film, andis characterized in that the transfer sheet comprises, at least, aninorganic component including a glass frit and an electricallyconductive powder, and an organic component removable by firing, and hasa surface gloss of 20 to 110.

[0019] Preferably, the transfer layer is characterized by having areleasable protective film thereon, and in that the surface gloss of thetransfer layer upon release of the protective film therefrom is in arange of 40 to 110.

[0020] Preferably, the organic component is characterized by beingsensitive to light.

[0021] The third transfer sheet of the invention comprises a base film,and a transfer layer releasably provided on the base film, whichtransfer layer comprises, at least, an inorganic component including aglass frit and an electrically conductive powder and an organiccomponent removable by firing, and has a surface glossiness of 20 to110. Thus, the transfer layer is improved in terms of surfacesmoothness; that is, it is substantially free of defects such asagglomerates, pinholes, etc. due to poor dispersion of the inorganiccomponent. When the transfer layer has a protective film thereon, airbubbles are unlikely to be trapped between the transfer layer and theprotective layer, so that the surface smoothness of the transfer layercan be kept in good condition with an improvement in the transferabilityof the transfer layer to an associated application member. It is thuspossible to form a primer or dielectric layer of uniform thickness. Whenthe organic component is sensitive to light, the accuracy of patterningby exposure and development is so improved that high-definition patternsfor electrodes, dielectric layers, etc., and high-definition thick-filmpatterns for barriers, etc. can be formed.

[0022] A fourth transfer sheet of the invention comprises, at least, abase film and a transfer layer releasably provided on the base film, andis characterized in that the transfer layer comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and a peel strength between the base film and thetransfer layer is in a range of 2 to 30 g/25 mm.

[0023] Preferably, the transfer layer is characterized by having areleasable protective film thereon, and that a peel strength between theprotective film and the transfer layer is in a range of 1 to 27 g/25 mmand smaller than the peel strength between the base film and thetransfer layer.

[0024] Preferably, the organic component is characterized by beingsensitive to light.

[0025] The fourth transfer sheet, designed for the fabrication of aplasma display panel, comprises a base film and a transfer layerreleasably provided on the base film, which transfer layer comprises, atleast, an inorganic component including a glass frit and an organiccomponent removable by firing, and has a peel strength in the range of 2to 30 g/25 mm. Thus, it is possible to transfer, with an improvedtransferability, the transfer layer to an associated application memberbecause the transfer layer can be released from the base film with nocohesive failure of the transfer layer. When the protective film isprovided on the transfer layer while the peel strength between them isin the range of 1 to 27 g/25 mm and smaller than that between the basefilm and the transfer layer, the protective film can be released fromthe transfer layer with no cohesive failure of the transfer layer andwith no release of the transfer layer from the base film. The release ofthe transfer layer from the base film, and the release of the protectivefilm from the transfer layer can be mechanically carried out in a stablemanner without any large tension variation because the peel strengthsare within the aforesaid ranges, so that the transfer layer can betransferred, with great transferability, to the associated applicationmember, thereby forming a dielectric layer of uniform thickness. Whenthe organic component is sensitive to light, the accuracy of patterningby exposure and development is so high that a high-definition dielectricpattern can be formed.

[0026] A fifth transfer sheet of the invention comprises a base film anda transfer layer releasably provided on the base film, and ischaracterized in that the transfer layer comprises, at least, aninorganic component including a glass frit and an electricallyconductive powder, and an organic component removable by firing, and apeel strength between the base film and the transfer layer is in a rangeof 0.2 g/25 mm to 30 g/25 mm inclusive.

[0027] Preferably, the transfer film is characterized by having areleasable protective film thereon, and in that a peel strength betweenthe protective film and the transfer layer is in a range of 0.1 g/25 mmto less than 30 g/25 mm and smaller than that between the base film andthe transfer layer.

[0028] Preferably, the organic component is characterized by beingsensitive to light.

[0029] The fifth transfer sheet of the invention comprises a base filmand a transfer layer releasably provided on the base film, whichtransfer layer comprises, at least, an inorganic component including aglass frit and an electrically conductive powder, and an organiccomponent removable by firing, and has a peel strength in the range of0.2 g/25 mm to 30 g/25 mm inclusive. Thus, it is possible to transfer,with an improved transferability, the transfer layer to an associatedapplication member because the transfer layer can be released from thebase film with no cohesive failure of the transfer layer. When theprotective film is provided on the transfer layer while the peelstrength between them is in the range of 0.1 g/25 mm to less than 30g/25 mm and smaller than that between the base film and the transferlayer, the protective film can be released from the transfer layer withno cohesive failure of the transfer layer and with no release of thetransfer layer from the base film. The release of the transfer layerfrom the base film, and the release of the protective film from thetransfer layer can be mechanically carried out in a stable mannerwithout any large tension variation because the peel strengths arewithin the aforesaid ranges, so that the transfer layer can betransferred, with great transferability, to the associated applicationmember, thereby forming a dielectric layer of uniform thickness. Whenthe organic component is sensitive to light, the accuracy of patterningby exposure and development is so high that a high-definition dielectricpattern can be formed.

[0030] A sixth transfer sheet of the invention comprises, at least, abase film and a transfer layer releasably provided on the base film, andis characterized in that the transfer layer comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and has a residual solvent content of at most 100mg/m².

[0031] Preferably, the transfer layer is characterized by having areleasable protective film thereon.

[0032] Preferably, the organic component is characterized by beingsensitive to light.

[0033] Preferably, the transfer layer is characterized by containing anelectrically conductive power as the inorganic component.

[0034] The sixth transfer sheet of the invention comprises a base filmand a transfer layer releasably provided on the base film, whichtransfer layer comprises, at least, an inorganic component including aglass frit and an organic component removable by firing, and has aresidual solvent content of at most 100 mg/m². Thus, the transfer layeris unlikely to break down by cohesion, and improved in terms of storagestability, and transferability with respect to the base film upontransfer. When the protective film is provided on the transfer layer, itcan be well released from the transfer layer. When the organic componentis sensitive to light, the accuracy of patterning by exposure anddevelopment is so high that high-definition patterns for electrodes,dielectric layers, etc., and high-definition thick-film patterns forbarriers, etc. can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a sectional schematic of one embodiment of the first tosixth transfer sheets of the invention.

[0036]FIG. 2 is a sectional schematic of another embodiment of the firstto sixth transfer sheets of the invention.

[0037]FIG. 3 is a perspective schematic of one example of a plasmadisplay panel.

[0038]FIG. 4 is a process sequence for illustrating one example ofelectrode pattern formation using the first, third, fifth, and sixthtransfer sheets of the invention.

[0039]FIG. 5 is a process sequence for illustrating one example ofdielectric layer formation using the first, second, fourth, and sixthtransfer sheets of the invention.

[0040]FIG. 6 is a process sequence for illustrating one example ofdielectric layer formation using the first, second, fourth, and sixthtransfer sheets of the invention.

[0041]FIG. 7 is a process sequence for illustrating one example ofelectrode pattern formation using the first, third, fifth, and sixthtransfer sheets of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042]FIG. 1 is a sectional schematic of one embodiment of the first tosixth transfer sheets of the invention, wherein a transfer sheet 1comprises a base film 2 and a transfer layer 3. FIG. 2 is a sectionalschematic of another embodiment of the first to sixth transfer sheets ofthe invention, wherein a transfer sheet 11 comprises a base film 12, atransfer layer 13 releasably provided on the base film 12, and aprotective film 14 releasably provided on the transfer layer 13.

[0043] The transfer sheet 1 or 11 may be in a sheet or continuous form.The continuous form of transfer sheet may be rolled around a core. Toprevent dusting or paper dusting in this case, the core may be made upof ABS resin, vinyl chloride resin, Bakelite, etc. Alternatively, aresin-impregnated paper tube or the like may be used to this end.

[0044] The first to sixth transfer sheets of the invention may besuitable for the formation, with great precision and ease, of electrodepatterns, dielectric layers, barrier layers, etc. in PDPs, FEDs, LCDS,fluorescent displays, hybrid integrated circuits, etc. A typicalapplication of the transfer sheet to an AC type PDP is explained justbelow.

[0045]FIG. 3 is a perspective schematic of an AC type PDP, wherein afront panel plate is spaced away from a back panel plate. As can be seenfrom FIG. 3, a PDP 51 comprises a front panel plate 61 and a back panelplate 71 which are parallel with, and in opposition to, each other. Theback panel plate 71 is vertically provided with barrier walls 76 on itsfront side, by which the front and back panel plates 61 and 71 arespaced away from each other at a given interval. The front panel plate61 comprises a front glass substrate 62, which is provided on its backside with a parallel array of composite electrodes consisting oftransparent electrodes or sustaining electrodes 63 and metal electrodesor bus electrodes 64. This electrode array is covered with a dielectriclayer 65, on which an MgO layer 66 is formed. The back panel plate 71comprises a back glass substrate 72, which is provided on its front sidewith a parallel array of address electrodes 74. The address electrodearray intersects at right angles with the composite electrode array viaa primer layer 73 and is located between the barrier walls 76. Theaddress electrode array is covered with a dielectric layer 75, and afluorescent layer 77 is provided over the surfaces of the barrier walls76 and the bottoms of cells. To put the AC type PDP into operation,given voltage is applied from an alternating current power sourcebetween the composite electrodes on the front glass substrate 62 to forman electric field, so that discharge can occur in cells defining displayelements divided by the front glass substrate 62, back glass substrate72 and barrier walls 76. Then, this discharge can give out ultravioletradiation, which in turn allows light to be emitted out of thefluorescent layer 77. The observer can observe this light passingthrough the front glass substrate 62.

[0046] While, in the example illustrated, the address electrodes 74 areformed on the back glass substrate 72 with the primer layer 73 locatedbetween them, it is understood that the address electrodes 74 may beprovided directly on the back glass substrate 72, i.e., with noprovision of the primer layer 73.

[0047] The first transfer sheet of the invention is explained. The firsttransfer sheet can be used for the formation of electrodes, resistorssuch as dielectric layers, barriers, etc. in image displays such as PDPsand LCDs, thermal heads, integrated circuits, etc.

[0048] Referring to FIG. 1, the transfer layer 3 is releasably providedon the base film 2. The transfer layer 3 comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and has a surface roughness Ra of at most 0.4 μm,and preferably at most 0.2 μm.

[0049] Referring then to FIG. 2, the transfer layer 13 comprises, atleast, an inorganic component including a glass frit and an organiccomponent removable by firing. The transfer layer 13 has a surfaceroughness Ra of at most 0.4 μm, and preferably at most 0.2 μm before theprotective film 14 is releasably laminated thereon, and a surfaceroughness Ra of at most 0.2 μm upon release of the protective film 14therefrom.

[0050] The transfer layer in the first transfer sheet 1 or 11 of theinvention has a surface roughness Ra of at most 0.4 μm (the surfaceroughness Ra of the transfer layer upon release of the protective filmtherefrom is at most 0.2 μm), and so is improved in terms of surfacesmoothness. In the transfer sheet 11, the trapping of air bubblesbetween the transfer layer 13 and the protective film 14 is preventedupon lamination of the protective film 14 on the transfer layer 13.Transfer of the transfer layer 3 or 13 (the transfer sheet 11 from whichthe protective film 14 is removed) to an associated application memberis achievable while they are in closer contact with each other, and thetrapping of air bubbles between them is prevented, resulting an improvedtransferability.

[0051] The surface roughness Ra of the transfer layer according to theinvention is given by a value found by use of Decktack 16000 made byBeeco Co., Ltd., and is an index to the surface smoothness of thetransfer layer 3 or 13. In other words, when the transfer layer 3 or 13has such defects as agglomerates or pinholes ascribable to poordispersion of the inorganic component, the surface roughness Ra exceeds0.4 μm due to a surface smoothness drop.

[0052] With the protective film 14 laminated on the transfer layer 13,the surface smoothness of the transfer layer 13 is usually improved.However, when the smoothness of the surface of contact of the protectivefilm 14 with the transfer layer 13 is unsatisfactory, the surfacesmoothness of the transfer layer 13 upon release of the protective film14 therefrom becomes worse, with the result that the surface roughnessRa of the transfer layer 13 exceeds 0.2 μm. This is the reason thesurface roughness Ra of the transfer layer 13 is preset at 0.4 μm orlower and the surface roughness Ra of the transfer layer 13 upon releaseof the protective film 14 therefrom is preset at 0.2 μm or lower. It isthus possible to obtain a transfer sheet comprising a transfer layerhaving improved surface properties.

[0053] Thus, the smaller the surface roughness Ra of the transfer layer3 or 13, the better the surface smoothness of the transfer layer is.However, when the surface roughness Ra is less than 0.01 μm or when thesurface roughness Ra of the transfer layer upon release of theprotective film therefrom is less than 0.005 μm, not only is anyadditional effect due to the improved surface smoothness expectable, butalso the fabrication cost may often increase, resulting in a fabricationyield drop. For this reason, the lower limit to the surface roughness Rais preferably about 0.01 μm, and the lower limit to the surfaceroughness Ra of the transfer layer upon release of the protective filmtherefrom is preferably about 0.005 μm.

[0054] The surface smoothness of the transfer layer 3 or 13 is affectedby the powder shape and content of the inorganic component, the type andcontent of the organic component, the solvent used, the coatingconditions applied, etc., as will be described later. It is thusrequired to form the transfer layer 3 or 13 under such conditions thatthe surface roughness Ra comes within the aforesaid range.

[0055] The structure of the first transfer sheet 1 or 11 of theinvention is now explained.

Base Film

[0056] For the base film 2 or 12 forming one part of the transfer sheet1 or 11 of the invention, it is required to use a material that isstable with respect to an ink composition used for the formation of thetransfer layer 3 or 13, and so flexible that it cannot substantially bedeformed under the influence of tension or pressure.

[0057] For such a material, a resin film is first exemplified. Exemplaryresin films are polyethylene films, ethylene-vinyl acetate copolymerfilms, ethylene-vinyl alcohol copolymer films, polypropylene films,polystyrene films, polymethacrylic ester films, polyvinyl chloridefilms, polyvinyl alcohol films, polyvinyl butyral films, nylon films,polyether ketone films, polyphenylene sulfide films, polysulfone films,polyether sulfone films, polytetrafluoroethylene-perfluoroalkylvinylether films, polyvinyl fluoride films, tetrafluoroethylene-ethylenefilms, tetrafluoroethylene-hexafluoropropylene films,polychlorotrifluoroethylene films, polyvinylidene fluoride films,polyethylene terephthalate films, 1,4-polycyclohexylenedimethyleneterephthalate films, polyethylene naphthalate films, polyester films,cellulose triacetate films, polycarbonate films, polyurethane films,polyimide films, and polyether imide films.

[0058] For use, these resin materials may be formed into films with theaddition of fillers thereto, they may be uniaxially or biaxiallyoriented into films, they may be biaxially oriented into films that arehigher in the percent of stretch in the widthwise direction than in thedirection of flow, and they may be biaxially oriented into films thatare higher in the percent of stretch in the direction of flow than inthe widthwise direction. The same or different films selected from thesefilms may be laminated together. The same or different resins selectedfrom the starting resins used for these films may be co-extruded intocomposite films.

[0059] Various treatments may be applied to the aforesaid resin films.For instance, silicone-treated polyethylene terephthalate films,corona-treated polyethylene terephthalate films, silicone-treatedpolypropylene films, and corona-treated polypropylene films may be used.

[0060] For the base film 2 or 12, it is also possible to use metalfoils, and metal steel bands. Exemplary metal foils and steel bands arecopper foils, copper steel bands, aluminum foils, aluminum steel bands,stainless steel bands such as SUS430, SUS301, SUS304, SUS420J2, andSUS631 steel bands, and beryllium steel bands. For use, the aforesaidresin films may be laminated on these metal foils or steel bands.

[0061] The base film 2 or 12 has a thickness of 4 to 400 μm, andpreferably 10 to 150 μm.

Transfer Layer

[0062] The transfer layer 3 or 13 comprises, at least, an inorganiccomponent including a glass frit and an organic component removable byfiring.

[0063] (1) Inorganic Component

[0064] For the glass frit, for instance, a glass frit having a softeningtemperature of 350 to 650° C. and a coefficient of thermal expansion_((χ) ₃₀₀ of 60×10⁻⁷ to 100×10⁻⁷/° C. may be used. A glass frit having asoftening temperature exceeding 650° C. is not preferable because thefiring temperature should be elevated. For instance, when the member tobe provided with a pattern has low heat resistance, it is thermallydeformed at the firing step. A glass frit having a softening temperatureof less than 350° C. is again not preferable, because voids are likelyto occur due to its thermal fusion before the organic component iscompletely decomposed and volatilized off by firing. A glass frit havinga coefficient of thermal expansion _((χ) ₃₀₀ of less than 60×10⁻⁷/° C.or greater than 100×10⁻⁷/° C. is not preferable because the member to beprovided with a pattern is often susceptible to distortion, etc. due totoo large a difference in the coefficient of thermal expansion betweenthe glass frit and the member. Preferably, the glass frit used in thepresent invention has an average particle size of 0.1 to 10 μm. For sucha glass frit, for instance, glass frits composed mainly of Bi₂O₃, ZnO orPbo may be used.

[0065] When such an alkaline development type photosensitive resincomposition as described later is used for the organic componentremovable by firing, it is preferable to use a bismuth type glass fritin view of its resistance to polymers, etc.

[0066] The transfer layer 3 or 13 may contain per 100 parts by weight ofglass frits at most 50 parts by weight of inorganic powders such asaluminum oxide, boron oxide, silica, titanium oxide, magnesium oxide,calcium oxide, strontium oxide, barium oxide, and calcium oxide powders.Such inorganic powders have preferably an average particle size of 0.1to 10 μm, and do not only act as an aggregate to prevent the patternfrom spreading during firing but have also a function of controllingreflectance and dielectric constant.

[0067] The transfer sheet 1 or 11 having the transfer layer 3 or 13comprising at least such glass frits as mentioned above for theinorganic component may be used for the fabrication of dielectric layersin plasma display panels.

[0068] When the transfer sheet 1 or 11 of the invention is used forbarrier formation, a refractory black or white pigment in an inorganicpowder form may be incorporated into the transfer layer 3 or 13 so thatthe amount of extraneous light reflected at the barrier pattern can bereduced with a practical contrast improvement. Exemplary refractoryblack pigments are Co—Cr—Fe, Co—Mn—Fe, Co—Fe—Mn—Al, Co—Ni—Cr—Fe,Co—Ni—Mn—Cr—Fe, Co—Ni—Al—Cr—Fe, and Co—Mn—Al—Cr—Fe—Si, and exemplaryrefractory white pigments are titanium oxide, aluminum oxide, silica,and calcium carbonate.

[0069] When the transfer sheet 1 or 11 of the invention is used forelectrode pattern formation, an electrically conductive powder in aninorganic powder form is incorporated into the transfer layer 3 or 13.

[0070] Exemplary conductive powders are Au powders, Ag powders, Cupowders, Ni powders, Al powders, and Ag—Pd powders, which may be usedalone or in combination of two or more. Such conductive powders may havevarious forms such as spherical, sheet, bulk, conical, and rod forms.However, preference is given to a spherical form of conductive powderthat is not susceptible to cohesion and is well dispersible, and has anaverage particle size of 0.05 to 10 μm, and preferably 0.1 to 5 μm. Thetransfer layer 3 or 13 may then contain 2 to 20 parts by weight, andpreferably 2 to 10 parts by weight of conductive powders per 100 partsby weight of glass frits.

[0071] (2) Organic Component

[0072] For the organic component contained in the transfer layer 3 or 13and removable by firing, a thermoplastic resin may be used.

[0073] The thermoplastic resin is used as a binder for the aforesaidinorganic component, and for the purpose of improving transferability.Exemplary thermoplastic resins are polymers or copolymers comprising atleast one of methyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, n-propyl acrylate, n-propyl methacrylate, isopropylacrylate, isopropyl methacrylate, n-butyl acrylate, n-butylmethacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butylacrylate, tert-butyl methacrylate, n-pentyl acrylate, n-pentylmethacrylate, n-hexyl acrylate, n-hexyl methacrylate, 2-ethylhexylacrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, n-octylmethacrylate, n-decyl acrylate, n-decyl methacrylate, 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,2-hydroxypropyl methacrylate, styrene, a-methylstyrene, andN-vinyl-2-pyrrolidone, and cellulose derivatives such as ethylcellulose.

[0074] Among others, particular preference is given to polymers orcopolymers comprising at least one of methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate,n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate,n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutylmethacrylate, tert-butyl acrylate, tert-butyl methacrylate,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, and 2-hydroxypropyl methacrylate, and ethyl cellulose.

[0075] Preferably, the thermoplastic resin used herein has a molecularweight of 10,000 to 500,000.

[0076] For the organic component contained in the transfer layer 3 or 13and removable by firing, a photosensitive resin composition, too, may beused.

[0077] The photosensitive resin composition contains the aforesaidthermoplastic resin, a monomer and an initiator, and is volatilized anddecomposed by firing, so that no carbide can remain in the film obtainedupon firing.

[0078] The alkaline development type photosensitive resin compositioncomprises, at least, an alkaline development type polymer, a monomer andan initiator, and is volatilzed and decomposed by firing, so that nocarbide can remain in the film obtained upon firing.

[0079] Exemplary alkaline development type polymers are polymers orcopolymers of at least one of methyl acrylate, methyl methacrylate,ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propylmethacrylate, isopropyl acrylate, isopropyl methacrylate, n-butylacrylate, n-butyl methacrylate, isobutyl acrylate, isobutylmethacrylate, tert-butyl acrylate, tert-butyl methacrylate, n-pentylacrylate, n-pentyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate,2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate,n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate,hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropylacrylate, hydroxypropyl methacrylate, styrene, α-methylstyrene, andN-vinyl-2-pyrrolidone and at least one of acrylic acid, methacrylicacid, a dimer of acrylic acid (e.g., M-5600 made by Toa Synethsis Co.,Ltd.), 2-methacryloyloxyethyl succinate, 2-acryloyloxyethyl succinate,2-methacryloyloxyethyl phthalate, 2-acryloyloxyethyl phthalate,2-methacryloyloxyethyl hexahydrophthalate, 2-acryloyloxyethylhexahydrophthalate, itaconic acid, crotonic acid, maleic acid, fumaricacid, vinyl acetate, and acid anhydrides thereof, and carboxylgroup-containing cellulose derivatives.

[0080] Use may also be made of polymers obtained by adding a glycidyl orhydroxyl group-containing ethylenically unsaturated compound to theaforesaid copolymers. However, the present invention is not limited tothese polymers.

[0081] The aforesaid polymers have a molecular weight of 5,000 to300,000, and preferably 30,000 to 150,000, and may be mixed with otherpolymers, for instance, methacrylic ester polymers, polyvinyl alcoholderivatives, N-methyl-2-pyrrolidone polymers, cellulose derivatives, andstyrene polymers.

[0082] For the reactive monomer forming a part of the photosensitiveresin composition, a compound having at least one polymerizablecarbon-carbon unsaturated bond may be used. Exemplary compounds areallyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxyethyleneglycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate,2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate,2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobutyl acrylate,isodecyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethylacrylate, methoxyethylene glycol acrylate, phenoxyethyl acrylate,stearyl acrylate, ethylene glycol diacrylate, diethylene glycoldiacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate,1,6-hexanediol diacrylate, 1,3-propanediol acrylate, 1,4-cyclohexanedioldiacrylate, 2,2-dimethylolpropane diacrylate, glycerol diacrylate,tripropylene glycol diacrylate, glycerol triacrylate, trimethylolpropanetriacrylate, polyoxyethylated trimethylolpropane triacrylate,pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethyleneoxide-modified pentaerythritol triacrylate, ethylene oxide-modifiedpentaerythritol tetraacrylate, propylene oxide-modified pentaerythritoltriacrylate, propylene oxide-modified pentaerythritol tetraacrylate,triethylene glycol diacrylate, polyoxypropyltrimethylolpropanetriacrylate, butylene glycol diacrylate, 1,2,4-butanetriol triacrylate,2,2,4-trimethyl-1,3-pentanediol diacrylate, diallyl fumarate,1,10-decanedioldimethyl acrylate, and pentaerythritol hexaacrylate, andcompounds wherein the acrylates in the above compounds are substitutedby methacrylates as well as γ-methacryloxypropyl trimethoxy silane, and1-vinyl-2-pyrrolidone. In the present invention, the above reactivemonomers may be used alone or in combination of two or more, and may beused in the form of mixtures with other compounds.

[0083] For the photopolymerization initiator forming another part of thephotosensitive resin composition, use may be made of combinations ofphoto-reducing dyes with reducing agents such as ascorbic acid,triethanolamine, etc. Exemplary photo-reducing dyes are benzophenone,methyl o-benzoylbenzoate, 4,4-bis(dimethylamine)benzophenone,4,4-bis(diethylamine)benzophenone, α-amino·acetophenone,4,4-dichlorobenzophenone, 4-benzoyl-4-methyl diphenyl ketone, dibenzylketone, fluorenone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone,p-tert-butyldichloroacetophenone, thioxanthone, 2-methythioxanthone,2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone,benzyldimethylketal, benzylmethoxyethylacetal, benzoin methyl ether,benzoin butyl ether, anthraquinone, 2-tert-butylanthraquinone,2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone,dibenzsuberone, methyleneanthrone, 4-azidobenzylacetophenone,2,6-bis(p-azidobenzylidene)cyclohexane,2,6-bis(p-azidobenzylidene)-4-methylcyclohexanone,2-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime,1-phenyl-propanedione-2-(o-ethoxycarbonyl)oxime,1,3-diphenyl-propanetrione-2-(o-ethoxycarbonyl)oxime,1-phenyl-3-ethoxyl-propanetrione-2-(o-benzoyl)oxime, Michler's ketone,2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,naphthalenesulfonyl chloride, quinolinesulfonyl chloride,n-phenylthioacridone, 4,4-azobisisobutyronitrile, diphenyl disulfide,benzothiazole disulfide, triphenylphosphine, camphorquinone, carbontetrabromide, tribromophenylsulfone, benzoyl peroxide, eosin, andmethylene blue. In the present invention, these photopolymerizationinitiators may be used alone or in combination of two or more.

[0084] The content of such a thermoplastic or photosensitive resincomposition in the transfer layer 3 or 13 is 5 to 50 parts by weight,and preferably 10 to 40 parts by weight per 100 parts by weight of theabove inorganic component. When the content of the thermoplastic orphotosensitive resin composition is below 5 parts by weight, the shaperetentivity of the transfer layer 3 or 13 becomes low, and a problemarises especially in connection with the storability and handleabilityof the transfer sheet in a rolled-up state. In addition, when thetransfer sheet 1 or 11 is slit to the desired shape, the transfer sheet1 or 11 manifests itself in dust form, which has in turn an adverseinfluence on the fabrication of plasma display panels. When the contentof the thermoplastic or photosensitive resin composition exceeds 50parts by weight, on the other hand, it is impossible to achieve completeremoval of the organic component by firing. consequently, the quality ofthe electrode pattern obtained upon firing drops because carbides remaintherein.

[0085] The above thermoplastic or photosensitive resin composition maycontain as optional additives photosensitizers, short-stoppers, chaintransfer agents, leveling agents, dispersants, transferability-impartingagents, stabilizers, anti-foaming agents, viscosity increasers,suspension agents and releasing agents, if required.

[0086] The transferability-imparting agent is added to the compositionfor the purpose of improving transferability, the fluidity of an inkcomposition, etc. Exemplary transferability-imparting agents are n-alkylphthalates such as dimethyl phthalate, dibutyl phthalate and di-n-octylphthalate; phthalic esters such as di-2-ethylhexyl phthalate,di-isodecyl phthalate, butylbenzyl phthalate, di-isononyl phthalate,ethyl phthalyl ethyl glycolate and butyl phthalyl butyl glycolate;trimellitic esters such as tri-2-ethylhexyl trimellitate, tri-n-alkyltrimellitate, tri-isononyl trimellitate and tri-isodecyl trimellitate;aliphatic dibasic acid esters such as dimethyl adipate, dibutyl adipate,di-2-ethylhexyl adipate, di-isodecyl adipate, dibutyl diglycol adipate,di-2-ethylhexyl azelate, dimethyl sebacate, dibutyl sebacate,di-2-ethylhexyl sebacate, di-2-ethylhexyl malate,acetyl-tri-(2-ethylhexyl)citrate, acetyl-tri-n-butyl citrate and acetyltributyl citrate; glycol derivatives such as polyethylene glycolbenzoate, triethylene glycol-di-(2-ethylhexoate) and polyglycol ether;glycerin derivative such as glycerol triacetate and glycerol diacetylmonolaurate; polyesters comprising sebacic acid, adipic acid, azelaicacid and phthallic acid; low-molecular-weight polyether having amolecular weight of 300 to 3,000, low-molecular-weight poly-α-styrenehaving the same molecular weight and low-molecular-weight polystyrenehaving the same molecular weight; orthophosphoric esters such astrimethyl phosphate, triethyl phosphate, tributyl phosphate,tri-2-ethylhexyl phosphate, tributoxyethyl phosphate, triphenylphosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenylphosphate, xylenyl diphenyl phosphate and 2-ethylhexyl diphenylphosphate; ricinoleic esters such as methyl acetyl ricinoleate;polyester-epoxidized esters such as poly-1,3-butanediol adipate andepoxidized soybean oil; and acetic esters such as glyerin triacetate and2-ethylhexyl acetate.

[0087] The dispersant and suspension agent are added to thethermoplastic or photosensitive resin composition for the purpose ofimproving the dispersion and suspension of the above inorganiccomponent. Exemplary dispersants and suspension agents are those basedon phosphoric esters, silicone, castor oil esters, and various surfaceactive agents. Exemplary anti-foaming agents are those based onsilicone, acrylics, and various surface active agents, exemplaryreleasing agents are those based on silicone, fluorine oils, paraffin,fatty acids, fatty esters, castor oils, waxes, and compounds, andexemplary leveling agents are those based on fluorine, silicone, andvarious surface active agents. These additives may be used in suitableamounts.

[0088] Solvents used with the thermoplastic or photosensitive resincomposition for the formation of the transfer layer 3 or 13, forinstance, are alcohols such as methanol, ethanol, n-propanol,isopropanol, ethylene glycol and propylene glycol; terpenes such as (α-or β-terpineol; ketones such as acetone, methyl ethyl ketone,cyclohexanone, N-methyl-2-pyrrolidone, diethyl ketone, 2-heptanone and4-heptanone; aromatic hydrocarbons such as toluene, xylene andtetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve,ethyl cellosolve, carbitol, methyl carbitol, ethyl carbitol, butylcarbitol, propylene glycol monomethyl ether, propylene glycol monoethylether, dipropylene glycol monomethyl ether, dipropylene glycol monoethylether, triethylene glycol monomethyl ether and triethylene glycolmonoethyl ether; acetic esters such as ethyl acetate, butyl acetate,cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate,carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate,propylene glycol monomethyl acetate, 2-ethoxyethyl acetate, cyclohexylacetate, 2-ethoxyethyl acetate and 3-methoxybuty acetate; ethyleneglycol dialkyl ether; dipropylene glycol dialkyl ether; ethyl3-ethoxypropionate; methyl benzoate; N,N-dimethylacetamide; andN,N-dimethylformamide.

[0089] The above transfer layer-forming components may be coated on thebase film 2 or 12 by known coating means such as direct gravure coating,gravure reverse coating, reverse roll coating, slide die coating, slitdie coating, comma coating, and slit reverse coating, and then dried.

[0090] The transfer layer is dried to a thickness of 5 μm to 25 μm forelectrode pattern formation, to a thickness of 10 μm to 100 μm fordielectric layer formation, and to a thickness of 70 μm to 300 μm forthe formation of a PDP barrier layer.

Protective Film

[0091] For the protective film 14 that forms the transfer sheet of theinvention, it is preferable to use a material that has such a surfaceproperty as to allow the surface gloss of the transfer layer 13 uponrelease of the protective film 14 therefrom to be confined within therange of 30 to 110 as measured by a gloss meter, and is flexible andless susceptible to large deformation under tension or pressure.Examples of such a material are polyethylene films, ethylene-vinylacetate copolymer films, ethylene-vinyl alcohol copolymer films,polypropylene films, polystyrene films, polymethacrylic ester films,polyvinyl chloride films, polyvinyl alcohol films, polyvinyl butyralfilms, nylon films, polyether ether ketone films, polysulfone films,polyether sulfone films, polytetrafluoroethylene-perfluoroalkylvinylether films, polyvinyl fluoride films, tetrafluoroethylene-ethylenefilms, tetrafluoroethylene-hexafluoropropylene films,polychlorotrifluoroethylene films, polyvinylidene fluoride films,polyethylene terephthalate films, cellulose triacetate films,polycarbonate films, polyurethane films, polyimide films, and polyetherimide films.

[0092] For use, these resin materials may be formed into films with theaddition of fillers thereto, they may be uniaxially or biaxiallyoriented into films, they may be biaxially oriented into films that arehigher in the percent of stretch in the widthwise direction than in thedirection of flow, and they may be biaxially oriented into films thatare higher in the percent of stretch in the direction of flow than inthe widthwise direction. The same or different films selected from thesefilms may be laminated together. The same or different resins selectedfrom the starting resins used for these films may be co-extruded intocomposite films. Of these films preference is given to biaxiallyoriented polyester films. Various treatments may be applied to theaforesaid resin films. For instance, silicone-treated polyethyleneterephthalate films, corona-treated polyethylene films, corona-treatedpolyethylene films, silicone-treated polypropylene films, andcorona-treated polypropylene films may be used. The protective film suchas one mentioned above should have preferably a thickness of 4 to 400μm, and preferably 6 to 150 μm.

[0093] The protective film may be either laminated directly on thetransfer layer or laminated on the transfer layer with an acrylic resinor other adhesive layer sandwiched between them.

[0094] Reference is then made to how to form a PDP electrode pattern anda dielectric layer, using the first transfer sheet of the invention.

[0095]FIG. 4 is a process sequence for the formation of a pattern for anaddress electrode 74 in a PDP back panel plate 71, using the firsttransfer sheet 11 of the invention. It is here to be noted that thetransfer layer 13 in the transfer sheet 11 contains a negativephotosensitive resin composition as the organic component removable byfiring, and that the address electrode 74 is formed directly on a backglass substrate 72.

[0096] Referring here to FIG. 4, a protective film 14 is first releasedfrom the transfer sheet 11. Then, the transfer sheet 11 is pressed on atransfer layer 3 side against the back glass substrate 72. Then, thetransfer layer 3 is transferred on the substrate 72 by release of a basefilm 12 from the transfer sheet (FIG. 4(A)). At this transfer step, thetransfer layer 3 can be well transferred to the substrate 72 because thesurface roughness Ra of the transfer layer 13 in the transfer sheet 11is at most 0.2 μm, so that the transfer layer 13 can be improved in thesurface smoothness of the side of the transfer layer 13 to betransferred and, hence, can be in closer contact with the back glasssubstrate 72.

[0097] It is here to be noted that when heating is needed for transferof the transfer layer 13 to the back glass substrate 72,the substrate 72may be heated independently or using a pressing roll.

[0098] Then, the transfer layer 13 is exposed to light using a photomaskM (FIG. 4(B)). It is here to be noted that when a light-transmittingfilm is used for the base film 12, the transfer layer 13 may be exposedto light before release of the base film 12 therefrom.

[0099] Subsequently, the transfer layer 13 is developed, thereby forminga pattern 3′ comprising a conductive photosensitive resin layer on theback glass substrate 72 (FIG. 4(C)). Finally, the pattern 3′ is fired toremove the organic component therefrom, thereby forming the addresselectrode pattern 74 (FIG. 4(D)).

[0100] In this embodiment of the invention, such a transfer sheet of theinvention as shown in FIG. 2 is used. When a transfer sheet having noprotective film thereon such as one shown in FIG. 1 is used, the patternmay be formed in the same operation as shown in FIG. 4 after the directpressing of the transfer layer in the transfer sheet against the backglass substrate 72.

[0101] Then, the formation of a dielectric layer 75 in the above PDPback panel plate 71 is explained.

[0102]FIG. 5 is a process sequence for the formation of the dielectriclayer 75, using the first transfer sheet of the invention.

[0103] Referring now to FIG. 5, a transfer sheet 1 is first pressed on atransfer layer 3 side against a back glass substrate 72 having anaddress electrode pattern 74 (FIG. 5(A)), after which a base film 2 isreleased therefrom to transfer the transfer layer 3 to the substrate 72,thereby obtaining a transfer pattern 3′ (FIG. 5(B)). At this transferstep, the transfer layer 3 can be well transferred to the substrate 72because the surface roughness Ra of the transfer layer 3 in the transfersheet 1 is at most 0.4 μm, so that the transfer layer 3 can be improvedin the surface smoothness of the side of the transfer layer 3 to betransferred and, hence, can be in closer contact with the back glasssubstrate 72 and the address electrode pattern 74. It is here to benoted that when heating is needed for transfer of the transfer layer 3to the back glass substrate 72, the substrate 72 may be heatedindependently or using a pressing roll.

[0104] Thereafter, the transfer pattern 3′ is fired to remove theorganic component therefrom to form the dielectric layer 75 (FIG. 5(C)).

[0105] In this embodiment of the invention, such a transfer sheet of theinvention as shown in FIG. 1 is used. When a transfer sheet having aprotective film thereon such as one shown in FIG. 2 is used, thedielectric layer may be formed in the same operation as shown in FIG. 5after release and removal of the protective film.

[0106] When a PDP barrier is formed using the transfer sheet of theinvention, either the transfer sheet having no protective film thereonor the transfer sheet having a protective film thereon may be used. Whenthe organic component of the transfer layer in the transfer sheet issensitive to light, the transferred layer is exposed to light in apattern form, developed, and finally fired, so that a given barrierpattern can be formed. When the organic component of the transfer layerin the transfer sheet is not sensitive to light, the transferred layeris etched as by sandblasting through a mask, and finally fired, so thata given barrier pattern can be formed.

[0107] The first transfer sheet of the invention are now explained withreference to Examples 1 to 3.

EXAMPLE 1

[0108] First, an ink composition composed of the following componentswas prepared as the ink composition for electrode pattern formation.Components of the Ink Composition Silver powders (in a spherical formhaving an 65 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  3 parts by weight of Bi₂O₃ andhaving a softening point of 500° C. and an average particle size of 1μm) n-Butyl methacrylate/2-hydroxypropyl methacrylate/  9 parts byweight methacrylic acid copolymer at a molar ratio of 6/2/2Pentaerythritol tri/tetraacrylate  8 parts by weight Photopolymerizationinitiator (Irgacure 369, Ciba-  1 parts by weight Geigy) 3-Methoxybutylacetate 20 parts by weight

[0109] Then, the above ink composition was coated by a blade coatingprocess on a polyethylene terephthalate film (T-60, Toray Industries,Inc.) provided as the base film, and dried at 80° C. for 2 minutes toform a transfer layer of 18 μm in thickness.

[0110] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) was laminated onthe transfer layer to form such a transfer sheet (sample 1) as shown inFIG. 2.

[0111] The above ink components were dispersed together under varyingdispersion conditions to prepare various ink compositions, which werethen used to make transfer sheets as mentioned above (sample 2, andcomparative samples 1 and 2). In comparative sample 1, the same inkcomposition as used to make sample 2 was used for transfer layerformation and the protective film used was a sand-matted polyethyleneterephthalate film (Type A, Toray Industries, Inc. ) having surfacesmoothness lower than that of the above protective film. Comparativesample 2 was prepared using an ink composition that was poorly dispersedby intention.

[0112] Such a transfer sheet (sample 3) as shown in FIG. 1, wherein atransfer layer was formed using the same ink composition as in sample 2with no protective film laminated thereon, was prepared together withsuch a transfer sheet (comparative sample 3) as shown in FIG. 1, whereina transfer layer was formed using the same ink composition as incomparative sample 2 with no protective film laminated thereon.

[0113] The surface roughness Ra of the transfer layer in each of thethus prepared transfer sheets (samples 1, 2, and comparative samples 1,2) before the protective films were laminated thereon, and the surfaceroughness Ra of the transfer layer in each of the transfer sheets(sample 3, and comparative sample 3) were measured by Dicktack 16000,Beeco Co., Ltd. Further, whether or not air bubbles were found in thetransfer sheets (samples 1, 2, and comparative samples 1, 2) with theprotective films laminated thereon was observed. The results arereported in Table 1.

[0114] Then, each of the above transfer sheets (samples 1, 2, andcomparative samples 1, 2) was slit to a given width, and rolled aroundan ABS resin core for storage at 25° C. for 30 days. Thereafter, theprotective film was released from each transfer sheet to measure thesurface roughness Ra of the transfer layer in the same manner asmentioned above. The results are also reported in Table 1.

[0115] After the above storage, the protective film was released fromeach of the transfer sheets (samples 1, 2, and comparative samples 1,2), which was then pressed on a glass substrate heated to 50° C., usingan auto-cutting laminator including a roll heated to 80° C. Similarly,each of the above transfer sheets (sample 3, and comparative sample 3)was slit to a given width, and pressed on a glass substrate heated to50° C., using an auto-cutting laminator including a roll heated to 80°C.

[0116] After each transfer sheet was cooled down to room temperature,the base film was released therefrom to transfer the transfer layer tothe glass substrate. At this transfer step, the transferability of eachof the transfer sheets (samples 1 to 3, and comparative samples 1 to 3)was observed. The results are shown in Table 1.

[0117] Then, the transfer layer was exposed to ultraviolet radiation of400 mJ/cm² (from a light source, i.e., a super high-pressuremercury-vapor lamp) via a negative pattern mask (with an opening linewidth of 90 μm) for plasma display panel electrodes. Following this, thetransfer layer was developed with a 0.5% aqueous solution of sodiumcarbonate to obtain a given pattern. Finally, the glass substrate wasfired at 600° C. to form an electrode pattern.

[0118] The appearance of the thus formed electrode pattern was observed.The results are shown in Table 1. TABLE 1 Surface Roughness Ra (μm)Appear- before after ance lamination of release of of Transferprotective protective Air Transfer- Electrode Sheet film film Bubblesability Pattern Sample 1 0.4 0.1 not good good found Sample 2 0.1 0.08not good good found Comp. 0.1 0.6 many many many Sample 1 bubblesbubbles defects found found and breaks found Comp. 0.8 0.3 many manymany Sample 2 bubbles bubbles defects found found and breaks foundSample 3 0.1 — — good good Comp. 0.8 — — many many Sample 3 bubblesdefects found and breaks found

[0119] From Table 1, it is found the first transfer sheets (samples 1,2) of the invention have no air bubbles trapped between the transferlayers and the protective films, and the transfer sheets of theinvention (samples 1 to 3) have satisfactory transferability to theglass substrates. It is also found that the electrode patterns obtainedusing these transfer sheets have uniform thicknesses and line widths,and are formed with high accuracy.

[0120] On the other hand, the transfer sheet (comparative sample 1)wherein the surface roughness Ra of the transfer layer before laminationof the protective film thereon is lower than 0.4 μm but the surfaceroughness Ra of the transfer layer upon release of the protective filmis greater than 0.2 μm, and the transfer sheet (comparative sample 2)wherein the surface roughness Ra of the transfer layer before laminationof the protective film thereon exceeds 0.4 μm and the surface roughnessRa of the transfer layer upon release of the protective film exceeds 0.2μm have air bubbles trapped between the transfer layer and theprotective film. The transfer sheets (comparative samples 1, 2 and 3)are found to be poor in transferability to the glass substrates becausethe transfer layers broken or were partly detached from the glasssubstrates. In addition, the electrode patterns formed using thesetransfer sheets are found to have many defects.

EXAMPLE 2

[0121] First, an ink composition having the following components wasprepared for dielectric layer formation. Components of the InkComposition Glass frits (of the non-alkali type composed mainly 65 partsby weight of Bi₂O₃, ZnO and B₂O₃ and having an average particle size of3 μm) n-Butyl methacrylate/2-hydroxyethyl methacrylate 15 parts byweight copolymer (at a molar ratio of 8/2) Adipate typetransferability-imparting agent 10 parts by weight (Adecaizer RS107,Asahi Denka Kogyo Co., Ltd.) TiO₂  7 parts by weight Al₂O₃  5 parts byweight Propylene glycol monomethyl ether 50 parts by weight

[0122] Then, the above ink composition was coated by a blade coatingprocess on a polyethylene terephthalate film (T-60, Toray Industries,Inc.) provided as the base film, and dried at 90° C. for 2 minutes toform a transfer layer of 30 μm in thickness.

[0123] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) of 25 μm inthickness was laminated on the transfer layer to form such a transfersheet (sample A) as shown in FIG. 2.

[0124] The above ink components were dispersed together under varyingdispersion conditions to prepare various ink compositions, which werethen used to make transfer sheets as mentioned above (sample B, andcomparative samples A and B). In comparative sample A, the same inkcomposition as in sample B was used for transfer layer formation and theprotective film used was a sand-matted polyethylene terephthalate film(Type A, Toray Industries, Inc. ) having surface smoothness lower thanthat of the above protective film. Comparative sample B was preparedusing an ink composition that was poorly dispersed by intention.

[0125] Such a transfer sheet (sample C) as shown in FIG. 1, wherein atransfer layer was formed using the same ink composition as in sample Bwith no protective film laminated thereon, was prepared together withsuch a transfer sheet (comparative sample C) as shown in FIG. 1, whereina transfer layer was formed using the same ink composition as incomparative sample B with no protective film laminated thereon.

[0126] The surface roughness Ra of the transfer layer in each of thethus prepared transfer sheets (samples A, B, and comparative samples A,B) before the protective films were laminated thereon, and the surfaceroughness Ra of the transfer layer in each of the transfer sheets(sample D, and comparative sample D) were measured in the same manner asin Example 1. Further, whether or not air bubbles were found in thetransfer sheets (samples A, B, and comparative samples A, b) with theprotective films laminated thereon was observed. The results arereported in Table 2.

[0127] Then, each of the above transfer sheets (samples A, B, andcomparative samples A, B) was slit to a given width, and rolled aroundan ABS resin core for storage at 25° C. for 30 days. Thereafter, theprotective film was released from each transfer sheet to measure thesurface roughness Ra of the transfer layer in the same manner as inExample 1. The results are also reported in Table 1.

[0128] After the above storage, the protective film was released fromeach of the transfer sheets (samples A, B, and comparative samples A,B), which was then pressed on a glass substrate (with an electrodepattern already formed thereon) heated to 100° C., using an auto-cuttinglaminator including a roll heated to 140° C. Similarly, each of theabove transfer sheets (sample C, and comparative sample C) was slit to agiven width, and pressed on a glass substrate (with an electrode patternalready formed thereon) heated to 100° C., using an auto-cuttinglaminator including a roll heated to 140° C.

[0129] After each transfer sheet was cooled down to room temperature,the base film was released therefrom to transfer the transfer layer tothe glass substrate. At this transfer step, the transferability of eachof the transfer sheets (samples A to C, and comparative samples A to C)was observed. The results are shown in Table 2.

[0130] Finally, each glass substrate was fired at 580° C. to form adielectric layer.

[0131] The surface states of the thus formed dielectric layers wereobserved. The results are shown in Table 2. TABLE 2 Surface Roughness Ra(μm) Appear- before after ance lamination of release of of Transferprotective protective Air Transfer- Electrode Sheet film film Bubblesability Pattern Sample A 0.4 0.1 not good good found Sample B 0.1 0.08not good good found Comp. 0.1 0.6 many many electrode Sample A bubblesbubbles partly found found bared with some variations Comp. 0.8 0.3 manymany electrode Sample B bubbles bubbles partly found found bared withsome variations Sample C 0.1 — — good good Comp. 0.8 — — many electrodeSample C bubbles partly found bared with some variations

[0132] From Table 2, it is found the first transfer sheets (samples A,B) of the invention have no air bubbles trapped between the transferlayers and the protective films, and the transfer sheets of theinvention (samples A to C) have satisfactory transferability to theglass substrates. It is also found that the dielectric layers obtainedusing these transfer sheets have uniform thicknesses, and satisfactorysurface flatness as well.

[0133] On the other hand, the transfer sheet (comparative sample A)wherein the surface roughness Ra of the transfer layer before laminationof the protective film thereon is lower than 0.4 μm but the surfaceroughness Ra of the transfer layer upon release of the protective filmis greater than 0.2 μm, and the transfer sheet (comparative sample B)wherein the surface roughness Ra of the transfer layer before laminationof the protective film thereon exceeds 0.4 μm and the surface roughnessRa of the transfer layer upon release of the protective film exceeds 0.2μm have air bubbles trapped between the transfer layer and theprotective film. The transfer sheets (comparative samples A, B and C)are found to be poor in transferability to the glass substrates becauseair bubbles are trapped between the transfer layers and the glasssubstrates (with electrodes formed thereon), and the close contact ofthe transfer layers with the glass substrates becomes worse. Inaddition, the dielectric layers used using these transfer sheets arefound to be not uniform even upon firing, and the electrodes were barein some spots.

EXAMPLE 3

[0134] First, an ink composition consisting of the following componentswas prepared as the ink composition for barrier formation. Components ofthe Ink Composition Glass frits (composed mainly of PbO, SiO₂ and 65parts by weight B₂O₃ and having an average particle size of 3 μm, asoftening point of 560° C. and a coefficient of thermal expansion of 65× 10⁻⁷/° C.) α-Alumina DA-40 (Iwatani Chemical Industries, 10 parts byweight Ltd.) Dipyrroxide Black #9510 (Dainichi Seika Kogyo 10 parts byweight Co., Ltd.) n-Butyl methacrylate/2-hydroxyethyl methacrylate  4parts by weight copolymer (at a molar ratio of 8/2) Di-2-ethylhexylphthalate (having a boiling point of  5 parts by weight 390° C.) Dibutylphthalate (having a boiling point of 282° C.)  3 parts by weightDipropylene glycol monomethyl ether 15 parts by weight

[0135] Then, the above ink composition was coated by a blade coatingprocess on a 75 μm thick polyethylene terephthalate film (T-60, TorayIndustries, Inc.) provided as the base film, and dried at 120° C. for 5minutes to form a transfer layer of 180 μm in thickness.

[0136] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) was laminated onthe transfer layer to form such a transfer sheet (sample I) as shown inFIG. 2.

[0137] The above ink components were dispersed together under varyingdispersion conditions to prepare various ink compositions, which werethen used to make transfer sheets as mentioned above (sample II, andcomparative samples I and II). In comparative sample I, the same inkcomposition as in sample II was used for transfer layer formation andthe protective film used was a sand-matted polyethylene terephthalatefilm (Type A, Toray Industries, Inc. ) having surface smoothness lowerthan that of the above protective film. Comparative sample II wasprepared using an ink composition that was poorly dispersed byintention.

[0138] Such a transfer sheet (sample III) as shown in FIG. 1, wherein atransfer layer was formed using the same ink composition as in sample IIwith no protective film laminated thereon, was prepared together withsuch a transfer sheet (comparative sample III) as shown in FIG. 1,wherein a transfer layer was formed using the same ink composition as incomparative sample II with no protective film laminated thereon.

[0139] The surface roughness Ra of the transfer layer in each of thethus prepared transfer sheets (samples I, II, and comparative samples I,II) before the protective films were laminated thereon, and the surfaceroughness Ra of the transfer layer in each of the transfer sheets(sample IV, and comparative sample IV) were measured as in Example 1.Further, whether or not air bubbles were found in the transfer sheets(samples I, II and comparative samples I, II) with the protective filmslaminated thereon was observed. The results are reported in Table 3.

[0140] Then, each of the above transfer sheets (samples I, II, andcomparative samples I, II) was slit to a given width, and rolled aroundan ABS resin core for storage at 25° C. for 10 days. Thereafter, theprotective film was released from each transfer sheet to measure thesurface roughness Ra of the transfer layer in the same manner as inExample 1. The results are also reported in Table 3.

[0141] After the above storage, the protective film was released fromeach of the transfer sheets (samples I, II, and comparative samples I,II), which was then pressed on a glass substrate (with the electrodepattern and dielectric layer already formed thereon) heated to 50° C.,using an auto-cutting laminator including a roll heated to 100° C.Similarly, each of the above transfer sheets (sample III, andcomparative sample III) was slit to a given width, and pressed on aglass substrate (with the electrode pattern and dielectric layer alreadyformed thereon) heated to 50° C., using an auto-cutting laminatorincluding a roll heated to 100 ° C.

[0142] After each transfer sheet was cooled down to room temperature,the base film was released therefrom to transfer the transfer layer tothe glass substrate. At this transfer step, the transferability of eachof the transfer sheets (samples I to III, and comparative samples I toIII) was observed. The results are shown in Table 3.

[0143] Subsequently, the glass substrate with the transfer layertransferred thereon was held in a 300° C. oven for 40 minutes forremoval of the high-boiling solvent. Using a roll heated to 120° C., anegative dry film resist with a protective film provided thereon (NCP225, Nippon Synthesis Chemistry Industries, Ltd.) was laminated on thetransfer layer. Then, a line mask pattern having a line width of 80 μmand a pitch of 220 μm was aligned with the photoresist layer forexposure to ultraviolet radiation (at a wavelength of 364 nm, anintensity of 200 μw/cm² and an exposure of 120 mJ/cm²). After release ofthe protective film from the photoresist layer, the transfer layer wasspray-developed using a 1% by weight aqueous solution of sodiumcarbonate maintained at a temperature of 30° C., thereby forming aresist pattern corresponding to the line pattern mask.

[0144] Using this resist pattern as a mask and brown fused alumina #800as an abrasive, the transfer layer was sand-blasted at an injectionpressure of 1 kg/cm². After the resist pattern was spray-released fromthe transfer layer in a 2% by weight aqueous solution of sodiumcarbonate kept at a temperature of 30° C., the transfer layer was washedwith water, then dried in an 80° C. oven for 15 minutes, and finallyfired at a peak temperature of 550° C to form a barrier pattern.

[0145] The appearance of the thus formed barrier patterns was observed.The results are shown in Table 3. TABLE 3 Surface Roughness Ra (μm)Appear- before after ance lamination of release of of Transferprotective protective Air Transfer- Barrier Sheet film film Bubblesability Pattern Sample I 0.4 0.1 not good good found Sample II 0.1 0.08not good good found Comp. 0.1 0.6 many many many Sample I bubblesbubbles breaks found found in the barrier local thinning of the barrierComp. 0.8 0.3 many many many Sample II bubbles bubbles breaks foundfound in the barrier local thinning of the barrier Sample III 0.1 — —good good Comp. 0.8 — — many many Sample III bubbles breaks found in thebarrier local thinning of the barrier

[0146] From Table 3, it is found that each of the first transfer sheets(sample I, and sample II) of the invention has no air bubbles trappedbetween the transfer layer and the protective film. Further, thetransfer sheets (samples I, II, and III) of the invention show goodtransferability with respect to the glass substrates. Furthermore, thebarrier patterns obtained using these transfer sheets were found to haveuniform thicknesses and line widths and are formed with high accuracy.

[0147] On the other hand, the transfer sheet (comparative sample I)wherein the surface roughness Ra of the transfer layer before laminationof the protective film thereon is lower than 0.4 μm but the surfaceroughness Ra of the transfer layer upon release of the protective filmtherefrom is greater than 0.2 μm, and the transfer sheet (comparativesample II) wherein the surface roughness Ra of the transfer layer beforelamination of the protective film thereon exceeds 0.4 μm and the surfaceroughness Ra of the transfer layer upon release of the protective filmtherefrom exceeds 0.2 μm have air bubbles trapped between the transferlayer and the protective film. The transfer sheets (comparative samplesI, II and III) are then found to be poor in transferability to the glasssubstrates due to breaks in the transfer layers, local peeling of thetransfer layers from the glass substrates, etc. Further, the barrierpatterns obtained using these transfer sheets are found to be poor inlinearity with many defects.

[0148] The second transfer sheet of the invention is then explained.With the second transfer sheet of the invention, it is possible to form,with high accuracy, primer layers, dielectric layers on front and backpanel plates, photosensitive black matrix layers, and photosensitive riblayers for use with PDPs.

[0149] It is currently required that dielectric layers for used withPDPs be fabricated at ever lower costs while their thickness and patternaccuracy is maintained at ever higher levels. The second transfer sheetof the invention is particularly suitable for forming dielectric layersfor PDPs with ease.

[0150] Referring to FIG. 1, the transfer layer 3 is releasably providedon the base film 2 and comprises, at least, an inorganic componentincluding a glass frit and an organic component removable by firing.This transfer layer 3 should then have a surface gloss between 20 and110, preferably 30 and 110, and more preferably 40 and 90.

[0151] Referring to FIG. 2, the surface gloss of the transfer layer 13before the protective film 14 is releasably provided thereon, and thesurface gloss of the transfer layer 13 after the protective film 14 isreleased therefrom should be between 30 and 110, and preferably between40 and 100.

[0152] That the surface glass of the transfer layer is in the range of20 to 110 (the surface gloss of the transfer layer from which theprotective film is released is in the range of 30 to 110) is tantamountto be that the surface smoothness of the transfer layer is improved forlack of defects such as agglomerates or pinholes due to poor dispersionof the inorganic component. Such a transfer layer serves well to preventair bubbles from being trapped between the transfer layer and theprotective film, and shows excellent transferability to an applicationsurface so that it can come into closer contact with the applicationsurface upon transfer.

[0153] A transfer sheet 1 or 11 of the invention has an improved surfacesmoothness because the surface gloss of the transfer layer is in therange of 20 to 110, as mentioned above. In the transfer sheet 11, it ispossible to prevent air bubbles from being trapped between the transferlayer 13 and the protective film 14 upon lamination of the protectivefilm 14 thereon. The transfer layer 3 or 13 shows excellenttransferability to an application surface so that it can come in closercontact with the application surface (the transfer layer of the transfersheet 11 from which the protective film 14 is removed shows excellenttransferability to the application surface).

[0154] In the present invention, the surface gloss of the transfer layeris represented by a value found using a gloss meter, VGS-1001DP made byNippon Denshoku Kogyo Co., Ltd., and is an index to the surfaceproperties of the transfer layer 3 or 13. When the transfer layer 3 or13 has surface defects such as agglomerates or pinholes due to poordispersion of the inorganic component, a drop of the surface smoothnessof the transfer layer is reflected on the surface gloss thereof; thesurface gloss of the transfer layer becomes lower than 20. Usually, thesurface smoothness of the transfer layer 13 is improved by provision ofthe protective film 14 thereon. When the smoothness of the surface ofcontact of the transfer layer 13 with the protective film 14 is in badcondition, however, the surface smoothness of the transfer layer 13 uponrelease of the protective film 14 therefrom becomes low. This is thenreflected on the surface gloss of the transfer layer 13; that is, thesurface gloss of the transfer layer 13 becomes lower than 30.

[0155] By ensuring that the surface gloss of the transfer layer 3 is 20or greater and the surface glass of the transfer layer 13 after releaseof the protective film 14 therefrom is 30 or greater, the transfer layerof the transfer sheet can thus be improved in the surface properties. Inother words, the higher the surface gloss of the transfer layer 3 or 13,the more improved the surface properties thereof are. At a surface glossexceeding 110, however, no further improvements in the surfaceproperties are expected; there are rather production cost increases orproduction yield reductions. It is consequently preferable that theupper limit to the surface gloss is about 110.

[0156] On the premise that the second transfer sheet of the invention isused for dielectric layer formation, the structures of the base film,transfer layer, and protective film thereof may be the same as alreadyexplained in conjunction with the first transfer sheet of the invention.However, it is to be understood that the surface gloss of the transferlayer 3 or 13 is affected by the powder shape and content of theinorganic component, the type and content of the organic component, thesolvent used, the coating conditions applied, etc., and so the transferlayer 3 or 13 should be formed under such conditions as to allow thesurface gloss to come within the aforesaid range.

[0157] Then, reference is made to how to form the dielectric layer 75 inthe PDP back plate 71 using the second transfer sheet of the invention.

[0158]FIG. 6 is a process sequence of how to form the dielectric layer75 using the transfer sheet 1 of the invention.

[0159] Referring here to FIG. 6, the transfer sheet 1 is first pressedon the side of the transfer layer 3 against the back glass substrate 72comprising a primer layer 73 and an address electrode pattern 74provided thereon. Then, the transfer layer 3 is transferred to thesubstrate 72 by release of the base film 2 from the transfer sheet 1(FIG. 6(A)). At this transfer step, the transfer layer 3 can be welltransferred to the substrate 72 because the surface gloss of thetransfer layer 3 in the transfer sheet 1 is in the range of 20 to 110,so that the transfer layer 3 can be improved in the surface smoothnessof the side of the transfer layer 3 to be transferred and, hence, can bein closer contact with the primer layer 73 and address electrode pattern74. When heating is needed for transfer of the transfer layer 3 on theback glass substrate 72, the substrate 72 may be heated independently orusing a pressing roll.

[0160] Then, the transfer layer 3 is exposed to light using a photomaskM (FIG. 6(B)). It is here to be noted that when a light-transmittingfilm is used for the base film 12, the transfer layer 3 may be exposedto light before release of the base film 12 therefrom.

[0161] Subsequently, the transfer layer 3 is developed, thereby forminga pattern 3′ comprising a photosensitive resin layer on the back glasssubstrate 72 (FIG. 6(C)). Finally, the pattern 3 is fired to remove theorganic component therefrom, thereby forming the dielectric layer 75(FIG. 6(D)).

[0162] In this embodiment of the invention, such a transfer sheet of theinvention as shown in FIG. 1 is used. When a transfer sheet having aprotective film thereon such as one shown in FIG. 2 is used, thedielectric layer may be formed in the same operation as shown in FIG. 6after release and removal of the protective film. Also, when thedielectric layer 75 is provided in a solid form rather than according tothe desired pattern, it is preferable to remove the organic component byfiring immediately after transfer of the transfer layer.

[0163] The second transfer sheet of the invention is now explained morespecifically with reference to Example 4.

EXAMPLE 4

[0164] First, an ink composition having the following components wasprepared for dielectric layer formation. Components of the InkComposition Glass frits (of the non-alkali type composed mainly 70 partsby weight of Bi₂O₃, ZnO and B203 and having an average particle size of3 μm) TiO₂  7 parts by weight Al₂O₃  5 parts by weight It is here to benoted that the above inorganic component mixture had a softening pointof 570° C., a glass transition temperature Tg of 485° C. and acoefficient of thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C. n-Butylmethacrylate/2-hydroxyethyl methacrylate 20 parts by weight copolymer(at a molar ratio of 8/2, and having a molecular weight of 300,000)Adipate type transferability-imparting agent 12 parts by weight(Adecaizer RS107, Asahi Denka Kogyo Co., Ltd.) Propylene glycolmonomethyl ether 50 parts by weight

[0165] Then, the above ink composition was coated by a blade coatingprocess on a polyethylene terephthalate film (T-60, Toray Industries,Inc.) provided as the base film, and dried at 100° C. for 2 minutes toform a transfer layer of 25 μm in thickness.

[0166] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) of 25 μm inthickness was laminated on the transfer layer to form such a transfersheet (sample 1) as shown in FIG. 2.

[0167] The above ink components were dispersed together under varyingdispersion conditions to prepare various ink compositions, which werethen used to make transfer sheets as mentioned above (samples 2 to 5).In particular, sample 4, and sample 5 were prepared using an inkcomposition that was poorly dispersed by intention.

[0168] The surface gloss of the transfer layer (before lamination of theprotective film thereon) in each of the thus prepared transfer sheets(samples 1 to 5) was measured, using a gloss meter (VGS-1001DP, NipponDenshoku Kogyo Co., Ltd.). Also, whether or not air bubbles were trappedbetween the transfer layer and the protective film laminated thereon wasobserved. The results are reported in Table 4.

[0169] Then, each of the above transfer sheets (samples 1 to 5) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 7 days. Thereafter, the protective film was released from eachtransfer sheet to measure the surface gloss of the transfer layer in thesame manner as mentioned above. The results are also reported in Table4.

[0170] After the above storage, the protective film was released fromeach of the transfer sheets, which was then pressed on a glass substrate(with an electrode pattern already formed thereon) heated to 100° C.,using an auto-cutting laminator including a roll heated to 40 ° C. Aftereach transfer sheet was cooled down to room temperature, the base filmwas released therefrom to transfer the transfer layer to the glasssubstrate. At this transfer step, the transferability of each of thetransfer sheets (samples 1 to 5) was observed. The results are shown inTable 4.

[0171] Finally, the glass substrate was fired at 570° C. to form andielectric layer.

[0172] The thickness, as measured, and surface state, as observed, ofeach of the thus formed dielectric layers are shown in Table 4. TABLE 4Surface Gloss before lamination of after release of Air Thickness ofSurface State of Transfer Sheet protective film protective film BubblesTransferability Dielectric Layer Dielectic Layer Sample 1 87 103 notfound good 20 μm good Sample 2 63 76 not found good 20 μm good Sample 323 40 not found good 20 μm good Sample 4 15 34 found poor close contact20 μm matted Sample 5 4.8 not laminated not laminated no transfer — —

[0173] From Table 4, it is found that each of the second transfer sheetsof the invention (samples 1 to 3) has no air bubbles trapped between thetransfer layer and the protective film, and shows good transferabilityto the glass substrate. The dielectric layers formed using thesetransfer sheets are all found to have uniform thicknesses andsatisfactory surface flatness.

[0174] On the other hand, the transfer sheet (sample 4) wherein thesurface gloss of the transfer layer before lamination of the protectivefilm thereon is less than 20 is found to have air bubbles trappedbetween the transfer layer and the protective film, and be poor intransferability to the glass substrate as well, due to breaks in thetransfer layer, poor close contact of the transfer layer with the glasssubstrate, etc. The dielectric layer formed using this transfer sheet(sample 4), too, is found to have air trapped between the transfer layerand the protective film, and be poor in close contact with the substrateeven upon firing. In sample 5, the transfer layer could neither belaminated thereon with the protective film, nor be transferred to theglass substrate.

[0175] Reference is then made to the third transfer sheet of theinvention. The third transfer sheet is preferable for electrode patternformation. Fine patterns such as electrode patterns for use with PDPsshould currently be formed with ever higher accuracy and at ever lowercosts. The third transfer sheet is particularly preferable for forming,with high accuracy, fine patterns such as electrode patterns for usewith PDPs.

[0176] Referring to FIG. 1, the transfer layer 3 is releasably providedon the base film 2 and comprises, at least, an inorganic componentincluding a glass frit and an organic component removable by firing.This transfer layer 3 should then have a surface gloss between 20 and110, preferably 30 and 90, and more preferably 60 and 90.

[0177] Referring to FIG. 2, the transfer sheet 11 comprises a base film12, a transfer layer 13 releasably provided on the base film 12, and aprotective film 14 releasably provided on the transfer layer 13. Thetransfer layer 13 comprises, at least, an inorganic component includinga glass frit and an organic component removable by firing. Then, thesurface gloss of the transfer layer 13 before a protective film 14 isreleasably provided thereon, and the surface gloss of the transfer layer13 after the protective film 14 is released therefrom should be between40 and 110, preferably 50 and 110, and more preferably 60 and 100.

[0178] The transfer sheet 1 or 11 of the invention has an improvedsurface smoothness because the surface gloss of the transfer layer is inthe range of 20 to 110, as mentioned above. In the transfer sheet 11, itis possible to prevent air bubbles from being trapped between thetransfer layer 13 and the protective film 14 upon lamination of theprotective film 14 thereon. The transfer layer 3 or 13 shows excellenttransferability to an application surface so that it can come in closercontact with the application surface (the transfer layer of the transfersheet 11 from which the protective film 14 is removed shows excellenttransferability to the application surface).

[0179] In the present invention, the surface gloss of the transfer layeris represented by a value found using a gloss meter as in the secondtransfer sheet, and is an index to the surface properties of thetransfer layer 3 or 13. When the transfer layer 3 or 13 has surfacedefects such as agglomerates or pinholes due to poor dispersion of theinorganic component, a drop of the surface smoothness of the transferlayer is reflected on the surface gloss thereof; the surface gloss ofthe transfer layer becomes lower than 20. When the smoothness of thesurface of contact of the transfer layer 13 with the protective film 14is in bad condition, air is locally trapped between them, resulting in atransfer failure By ensuring that the surface gloss of the transferlayer 3 or 13 is 20 or greater, the transfer layer of the transfer sheetcan thus be improved in the surface properties. In other words, thehigher the surface gloss of the transfer layer 3 or 13, the moreimproved the surface properties thereof are. At a surface glossexceeding 110, however, no further improvements in the surfaceproperties are expected; there are rather production cost increases orproduction yield reductions. It is consequently preferable that theupper limit to the surface glass is about 110.

[0180] On the premise that the third transfer sheet of the invention isused for electrode pattern formation, the structures of the base film,transfer layer, and protective film thereof may be the same as alreadyexplained in conjunction with the first transfer sheet of the invention.However, it is to be understood that the surface gloss of the transferlayer 3 or 13 is affected by the powder shape and content of theinorganic component, the type and content of the organic component, thesolvent used, the coating conditions applied, etc., and so the transferlayer 3 or 13 should be formed under such conditions as to allow thesurface gloss to come within the aforesaid range of 20 to 110.

[0181] Then, reference is made to how to form a PDP electrode patternusing the third transfer sheet of the invention.

[0182]FIG. 7 is a process sequence of how to form a pattern for theaddress electrode 74 using the transfer sheet 1 of the invention. It ishere to be noted that the transfer layer 3 of the transfer sheet 1contains a negative photosensitive resin composition as the organiccomponent removable by firing.

[0183] Referring here to FIG. 7, the transfer sheet 1 is first pressedon the side of the transfer layer 3 against the back glass substrate 72comprising a primer layer 73. Then, the transfer layer 3 is transferredto the substrate 72 by release of the base film 2 from the transfersheet 1 (FIG. 7(A)). At this transfer step, the transfer layer 3 can bewell transferred to the substrate 72 because the surface gloss of thetransfer layer 3 in the transfer sheet 1 is in the range of 20 to 110,so that the transfer layer 3 can be improved in the surface smoothnessof the side of the transfer layer 3 to be transferred and, hence, can bein closer contact with the primer layer 73. When heating is needed fortransfer of the transfer layer on the back glass substrate 72, thesubstrate 72 may be heated independently or using a pressing roll.

[0184] Then, the transfer layer 3 is exposed to light using a photomaskM (FIG. 7(B)). It is here to be noted that when a light-transmittingfilm is used for the base film 2, the transfer layer 3 may be exposed tolight before release of the base film 2 therefrom.

[0185] Subsequently, the transfer layer 3 is developed, thereby forminga pattern 3′ comprising a photosensitive resin layer on the primer layer73 (FIG. 7(C)). Finally, the pattern 3 is fired to remove the organiccomponent therefrom, thereby forming the address electrode pattern 74(FIG. 7(D)).

[0186] In this embodiment of the invention, such a transfer sheet of theinvention as shown in FIG. 1 is used. When a transfer sheet having aprotective film thereon such as one shown in FIG. 2 is used, theelectrode pattern may be formed in the same operation as shown in FIG. 7after release and removal of the protective film.

[0187] Then, the third transfer sheet of the invention is explained morespecifically to Example 5.

EXAMPLE 5

[0188] A photosensitive resin composition consisting of the followingcomponents was prepared for an ink composition. Components of thePhotosensitive Resin Composition Silver powders (in a spherical formhaving an 96 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  4 parts by weight of Bi₂O₃,SiO₂ and B₂O₃ and having a softening point of 500° C.) n-Butylmethacrylate/2-hydroxypropyl methacrylate/ 13 parts by weightmethacrylic acid copolymer (with glycidyl methacrylate added thereto,and having a molecular weight of 80,000 and an acid number of 110mgKOH/g) Pentaerythritol tri/tetraacrylate 11 parts by weightPhotopolymerization initiator (Irgacure 369,  1 part by weightCiba-Geigy) 3-Methoxybutyl acetate 20 parts by weight

[0189] Then, the above photosensitive resin composition was coated by ablade coating process on a polyethylene terephthalate film (T-60, TorayIndustries, Inc.) provided as the base film, and dried at 100° C. for 2minutes to form a transfer layer of 11 μm in thickness.

[0190] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) was laminated onthe transfer layer to form such a transfer sheet (sample 1) as shown inFIG. 2.

[0191] The above photosensitive resin components were dispersed togetherunder varying dispersion conditions to prepare various photosensitivecompositions, which were then used to make transfer sheets as mentionedabove (samples 2 to 5). In particular, sample 4, and sample 5 wereprepared using a photosensitive resin composition that was poorlydispersed by intention.

[0192] The surface gloss of the transfer layer (before transfer of theprotective film thereon) in each of the thus prepared transfer sheets(samples 1 to 5) was measured, using a gloss meter (VGS-1001DP, NipponDenshoku Kogyo Co., Ltd.). Also, whether or not air bubbles were trappedbetween the transfer layer and the protective film laminated thereon wasobserved. The results are reported in Table 5.

[0193] Then, each of the above transfer sheets (samples 1 to 5) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 1 day. Thereafter, the protective film was released from eachtransfer sheet to measure the surface gloss of the transfer layer in thesame manner as mentioned above. The results are also reported in Table5.

[0194] After the above storage, the protective film was released fromeach of the transfer sheets, which was then pressed on a glass substrateheated to 40° C., using an auto-cutting laminator including a rollheated to 40° C. After each transfer sheet was cooled down to roomtemperature, the base film was released therefrom to transfer thetransfer layer to the glass substrate. At this transfer step, thetransferability of each of the transfer sheets (samples 1 to 5) wasobserved. The results are shown in Table 5.

[0195] Subsequently, the transfer layer was exposed to ultravioletradiation of 700 mJ/cm² (from a light source, i.e., a superhigh-pressure mercury-vapor lamp) via a negative pattern mask (with anopening line width of 90 μm) for plasma display panel electrodes. Then,the transfer layer was developed with a 0.5% aqueous solution of sodiumcarbonate to obtain a given pattern. Finally, the glass substrate wasfired at 600° C. to form an electrode pattern.

[0196] The thicknesses and line widths, as measured, of the thus formedelectrode patterns are shown in Table 5. TABLE 5 Surface Gloss beforelamination of after release of Air Thickness of Line Width of TransferSheet protective film protective film Bubbles Transferability Electrodepattern Electrode Pattern Sample 1 87 100 not found good 7 ± 1 μm 65 ± 2μm Sample 2 50 80 not found good 7 ± 1 μm 65 ± 2 μm Sample 3 25 50 notfound good 7 ± 1 μm 65 ± 2 μm Sample 4 15 35 many found many defectsfound (*) — — Sample 5 10 25 many found no partial transfer — —

[0197] From Table 5, it is found that each of the third transfer sheetsof the invention (samples 1 to 3) have no air bubbles trapped betweenthe transfer layer and the protective film, and shows goodtransferability with respect to the glass substrate. The electrodepatterns formed using these transfer sheets are all found to haveuniform thicknesses and line widths, and have high accuracy as well.

[0198] On the other hand, the transfer sheet (sample 4 or 5) wherein thesurface gloss of the transfer layer is less than 20 is found to have airbubbles trapped between the transfer layer and the protective film, andbe poor in transferability with respect to the glass substrate as well,due to breaks in the transfer layer, local peeling of the transferlayer, etc. The electrode patterns formed using these transfer sheetsare found to be poor in linearity with many defects.

[0199] Then, the fourth transfer sheet of the invention is explained.Like the second transfer sheet of the invention, the fourth transfersheet of the invention is particularly preferable for forming, with highaccuracy, primer layers, dielectric layers on front and back plates,photosensitive black matrix layers, and photosensitive rib layers foruse with PDPs.

[0200] Referring here to FIG. 1, the transfer layer 3 comprises, atleast, an inorganic component including a glass frit and an organiccomponent removable by firing, and the peel strength of the transferlayer 3 with respect to the base film 2 should be between 2 g/25 mm and30 g/25 mm, and preferably 4 g/25 mm and 20 g/25 mm.

[0201] Referring to FIG. 2, the transfer layer 13 comprises, at least,an inorganic component including a glass frit and an organic componentremovable by firing. Then, the peel strength of the transfer layer 13with respect to the base film 12 should be between 2 g/25 mm and 30 g/25mm, and preferably 4 g/25 mm and 20 g/25 mm while the peel strength ofthe transfer layer 13 with respect to the protective film 14 should bebetween 1 g/25 mm and 27 g/25 mm, and preferably 1 g/25 mm and 15 g/25mm, and be lower than the peel strength of the transfer layer 13 withrespect to the base film 12.

[0202] When the peel strength of the transfer layer 3 or 13 with respectto the base film 2 or 12 is below 2 g/25 mm, the handleability of thetransfer sheet 1 or 11 becomes worse due to the possibility ofunnecessary peeling-off or coming-off of the transfer layer 3 or 13.When the peel strength exceeds 30 g/25 mm, a cohesive failure of thetransfer layer 3 or 13 is likely to occur upon release of the transferlayer 3 or 13 from the base film 2 or 12. When the transfer layer 3 or13 is released from the base film 2 or 12 using a machine, large loadshould be applied on the machine so as to release the transfer layer 3or 13 from the base film 2 or 12 stably at such high peeling strength.

[0203] When the peel strength of the transfer layer 13 with respect tothe protective film 14 is below 1 g/25 mm, on the other hand, thehandleability of the transfer sheet 11 becomes worse because of thepossibility of unnecessary peeling-off or coming-off of the protectivefilm 14. When the peel strength is greater than 27 g/25 mm, a cohesivefailure of the transfer layer 13 is likely to occur upon release of theprotective film 14 from the transfer layer 13. When the protective film14 is released from the transfer layer 13 using a machine, it isdifficult to provide a stable release of the protective film 14 from thetransfer layer 13 due to large tension variations. Preferably, the peelstrength of the transfer layer 13 with respect to the protective film 14should be lower than the peel strength of the transfer layer 13 withrespect to the base film 12 by at least 1 g/25 mm.

[0204] With the transfer sheet 1 or 11 of the invention, the transferlayer 3 or 13 can be released from the base film 2 or 12 with nocohesive failure of the transfer layer 3 or 13. With the transfer sheet11 having the protective film 14 placed on the transfer layer 13, theprotective film 14 can be released from the transfer layer 13 with norelease of the transfer layer 13 from the base film 12, and no cohesivefailure of the transfer layer 13.

[0205] It is to be noted that the peel strength referred to herein is avalue found by peeling off a sample of 25 mm in width through 180° at aspeed of 100 mm/min., using a large Tensiron universal testing machineUTM-500, Toyo Baldwin Co., Ltd.

[0206] On the premise that the fourth transfer sheet of the invention isused primarily for dielectric layer formation, the structures of thebase film, transfer layer, and protective film therein may be the sameas explained in conjunction with the first transfer sheet of theinvention. The peel strength of the transfer layer 3 or 13 with respectto the base film 2 or 12 can be regulated within the above range of 2 to30 g/25 mm depending on the content of the inorganic component in thetransfer layer 3 or 13, the type and content of the organic componenttherein, the solvent used, and the coating conditions applied and/or thematerial and surface state of the base film 2 or 12.

[0207] The peel strength of the transfer layer 13 with respect to theprotective film 14, too, can be regulated within the above range of 1g/25 mm to 27 g/25 mm depending on the content of the inorganiccomponent in the transfer layer 13, the type and content of the organiccomponent therein, the solvent used, and the coating conditions appliedand/or the material and surface state of the protective film 14.

[0208] The protective film 14 that forms one part of the fourth transfersheet of the invention may be made up of a material that has suchsurface properties as to allow its peel strength with respect to thetransfer layer 13 to be between 1 g/25 mm and 27 g/25 mm, and isflexible and less susceptible to large deformation under tension orpressure.

[0209] Reference is made to how to form the dielectric layer 75 in thePDP back panel plate 71 using the fourth transfer sheet of theinvention.

[0210]FIG. 6 is a process sequence of how to form the dielectric layer75 using the third transfer sheet of the invention, as in the case ofthe second transfer sheet of the invention. It is here to be noted thatthe transfer layer 3 in the transfer sheet 1 contains a negativephotosensitive resin composition as the organic component removable byfiring.

[0211] Referring to FIG. 6, the transfer sheet 1 is pressed on itstransfer layer 3 side against the back glass substrate 72 comprising aprimer layer 73 and an address electrode pattern 74 formed thereon,after which the base film 2 is released from the transfer sheet 1 fortransfer of the transfer layer 3 (FIG. 6(A)). At this transfer step, thetransfer layer 3 can be well transferred on the glass substrate with nocohesive failure of the transfer layer 3 because the peel strengthbetween the base film 2 and the transfer layer 3 is in the range of 2 to30 g/25 mm. It is here to be noted that when heating is needed fortransfer of the transfer layer 3, the back glass substrate 72 may beheated independently or using a pressing roll.

[0212] Then, the transfer layer 3 is exposed to light via a photomask M(FIG. 6(B)). It is here to be noted that when a light-transmitting filmis used as the base film 2, it may be exposed to light before a releaseof the base film 2 therefrom.

[0213] Subsequently, the transfer layer 3 is developed, thereby forminga pattern 3′ on the primer layer 73 and address electrode pattern 74(FIG. 6(C)). Finally, the pattern 3 is fired to remove the organiccomponent therefrom, thereby forming the dielectric layer 75 (FIG.6(D)).

[0214] In the above embodiment, such a transfer sheet of the inventionas shown in FIG. 1 is used. However, it is to be understood that whenthe transfer sheet 11 having the protective film 14 thereon such as oneshown in FIG. 2 is used, the dielectric layer may be formed in the sameoperation as in FIG. 6 after release and removal of the protective film14.

[0215] The protective film 14 can be well released from the transferlayer 13 with no cohesive failure of the transfer layer 13 and with thetransfer layer 13 remaining fixed to the base film 12, because the peelstrength between the protective film 14 and the transfer layer 13 is inthe range of 1 to 27 g/25 mm and is lower than that between the basefilm 12 and the transfer layer 13.

[0216] In this regard, it is to be understood that when the dielectriclayer 75 is provided in a full-solid form rather than according to thedesired pattern, the organic component can be removed by firingimmediately after transfer of the transfer layer.

[0217] The present invention is now explained more specifically withreference to Example 6.

EXAMPLE 6

[0218] An ink composition A consisting of the following components wasprepared. Components of the Ink Composition A Glass frits (of thenon-alkali type composed mainly 70 parts by weight of Bi₂O₃, ZnO andB₂O₃ and having an average particle size of 3 μm) TiO₂  7 parts byweight Al₂O₃  5 parts by weight

[0219] It is here to be noted that the above inorganic component mixturehad a softening point of 570° C., a glass transition temperature Tg of485° C. and a coefficient of thermal expansion _((χ) ₃₀₀ of 80×10⁻⁷/° C.n-Butyl methacrylate/2-hydroxyethyl methacrylate 20 parts by weightcopolymer (at a molar ratio of 8/2, and having a molecular weight of300,000) Adipate type transferability-imparting agent 12 parts by weight(Adecaizer RS107, Asahi Denka Kogyo Co., Ltd.) Propylene glycolmonomethyl ether 50 parts by weight

[0220] Then, the above ink composition A was coated by a blade coatingprocess on a polyethylene terephthalate film (T-60, Toray Industries,Inc.) provided as the base film, and dried at 100° C. for 2 minutes toform a transfer layer of 17 μm in thickness.

[0221] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) of 25 μm inthickness was laminated on the transfer layer to form such a transfersheet (sample 1) as shown in FIG. 2.

[0222] An ink composition B consisting of the following components wasthen prepared to form a transfer sheet (sample 2) in the same manner asmentioned above with the exception that a 30 μm thick polyethylene film(GF-1, Tamapoly Co., Ltd.) was used for the protective film. Componentsof the Ink Composition B Glass frits (of the non-alkali type composedmainly 70 parts by weight of Bi₂O₃, ZnO and B₂O₃ and having an averageparticle size of 3 μm) TiO₂  7 parts by weight Al₂O₃  5 parts by weight

[0223] It is here to be noted that the above inorganic component mixturehad a softening point of 570° C., a glass transition temperature Tg of485° C. and a coefficient of thermal expansion _((χ) ₃₀₀ of 80×10⁻⁷/° C.n-Butyl methacrylate/2-hydroxyethyl methacrylate 20 parts by weightcopolymer (at a molar ratio of 8/2, and having a molecular weight of50,000) Adipate type transferability-imparting agent 12 parts by weight(Adecaizer RS107, Asahi Denka Kogyo Co., Ltd.) Propylene glycolmonomethyl ether 50 parts by weight

[0224] A transfer sheet (sample 3) was prepared using the above inkcomposition A and in the same manner as mentioned above, with theexception that a 25 μm thick melamine-treated polyethylene terephthalatefilm (25SG-1, Panack Co., Ltd.) was used for the base film.

[0225] A transfer sheet (sample 4) was also prepared using the above inkcomposition A and in the same manner as mentioned above, with theexception that a 25 μm thick silicone-treated polyethylene terephthalatefilm (SP-PET-03-25-C, Tosero Co., Ltd.) was used for the base film and a25 μm thick silicone-treated polyethylene terephthalate film(SP-PET-03-25-Bu, Tosero Co., Ltd.) was used for the protective film.

[0226] Furthermore, an ink composition C consisting of the followingcomponents was prepared to form a transfer sheet (sample 5) as in thecase of sample 1. Components of the Ink Composition C Glass frits (ofthe non-alkali type composed mainly 70 parts by weight of Bi₂O₃, ZnO andB₂O₃ and having an average particle size of 3 μm) TiO₂  7 parts byweight Al₂O₃  5 parts by weight

[0227] It is here to be noted that the above inorganic component mixturehad a softening point of 570° C., a glass transition temperature Tg of485° C. and a coefficient of thermal expansion _((χ) ₃₀₀ of 80×10⁻⁷/° C.n-Butyl methacrylate/2-hydroxyethyl methacrylate 20 parts by weightcopolymer (at a molar ratio of 8/2, and having a molecular weight of20,000) Adipate type transferability imparting agent  9 parts by weight(Adecaizer RS107, Asahi Denka Kogyo Co., Ltd.) Propylene glycolmonomethyl ether 50 parts by weight

[0228] Then, each of the above transfer sheets (samples 1 to 5) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 7 days. Regarding each of the transfer sheets (samples 1 to 5),the peel strength between the base film and the transfer layer, and thepeel strength between the protective film and the transfer layer weremeasured under the following conditions. The results are reported inTable 6.

Conditions for Measurement of Peel Strength

[0229] A sample of 25 mm in width was cut out of each transfer sheet inits flow direction, and then peeled through 180° at a speed of 100mm/min., using a large Tensiron universal testing machine UTM-500, ToyoBaldwin Co., Ltd. to measure its peel strength.

[0230] After the above storage, the protective film was then releasedfrom the transfer sheet, which was in turn pressed against a glasssubstrate heated to 80° C. (with an electrode pattern already formedthereon), using an auto-cutting laminator having a roll heated to 40° C.Following this, the glass substrate was cooled down to room temperatureto transfer the transfer layer to the glass substrate after release ofthe base film therefrom. At this transfer step, the releasability of theprotective film from each of the transfer sheets (samples 1 to 5), andthe transferability of the transfer layer therefrom (including thetransferability of the base film) were observed. The results arereported in Table 6.

[0231] Finally, the glass substrate was fired at 570° C. to form adielectric layer.

[0232] The thicknesses and surface states, as measured, of thedielectric layers formed in this manner are also shown in Table 6. TABLE6 peel strength (g/25 mm) Base vs. Protection vs. Transfer- Thickness ofSurface State of Transfer Sheet Transfer Layer Transfer LayerReleasability* ability Dielectric Layer Dielectric Layer Sample 1 10 1.5good good 20 μm good Sample 2 26 21 good good 20 μm good Sample 3 3.51.5 good good 20 μm good Sample 4 1.5 0.5 bad (*1) bad 20 μm air trappedSample 5 48 29 bad bad (*2) 20 μm bad (*3)

[0233] From Table 6, it is found that each of the fourth transfer sheets(samples 1 to 3) of the invention are excellent in the releasability ofthe protective film from the transfer layer, and in the transferabilityof the transfer layer to the glass substrate as well. The dielectriclayers formed using these transfer sheets, too, are found to haveuniform thicknesses and good surface flatness.

[0234] The transfer sheet (sample 4) wherein the peel strength betweenthe base film and the base film is less than 2 g/25 mm and the peelstrength between the protective film and the transfer layer is less than1 g/25 mm is unsatisfactory because air is likely to be trapped thereindue to poor adhesion between the transfer layer and the base film, andpoor adhesion between the transfer layer and the protective layer.

[0235] On the other hand, an ordinary releasing machine or laminator canhardly be used with the transfer sheet (sample 5) designed for PDPfabrication, in which the peel strength between the base film and thetransfer layer is greater than 30 g/25 mm and the peel strength betweenthe protective film and the transfer layer is greater than 27 g/25 mm,because the force needed to release the protective film, and base filmfrom the transfer layer becomes too large. The surface state of thedielectric layer formed is found to be adversely affected by perceptiblepeeling traces on the transfer layer upon peeling.

[0236] Then, the fifth transfer sheet of the invention is explained.Like the third transfer sheet of the invention, the fifth transfer sheetof the invention is particularly preferable for forming, with highaccuracy, primer layers, dielectric layers on front and back plates,photosensitive black matrix layers, and photosensitive rib layers foruse with PDPs.

[0237] Referring here to FIG. 1, the transfer layer 3 comprises, atleast, an inorganic component including a glass frit and an electricallyconductive powder, and an organic component removable by firing, and thepeel strength of the transfer layer 3 with respect to the base film 2should be between 0.2 g/25 mm and 30 g/25 mm, preferably 1.0 g/25 mm and10 g/25 mm, and even more preferably 2.0 g/25 mm and 15 g/25 mm.

[0238] Referring to FIG. 2, the transfer layer 13 comprises, at least,an inorganic component inclusive of a glass frit and an electricallyconductive powder, and an organic component removable by firing. Then,the peel strength of the transfer layer 13 with respect to the base film12 should be between 0.2 g/25 mm and 30 g/25 mm, and preferably 1.0 g/25mm and 10 g/25 mm while the peel strength of the transfer layer 13 withrespect to the protective film 14 should be between 0.1 g/25 mm and lessthan 30 g/25 mm, preferably 0.2 g/25 mm and 10 g/25 mm, and morepreferably 0.5 g/25 mm and 8 g/25 mm, and be lower than the peelstrength of the transfer layer 13 with respect to the base film 12.

[0239] When the peel strength of the transfer layer 3 or 13 with respectto the base film 2 or 12 is below than 0.2 g/25 mm, the handleability ofthe transfer sheet 1 or 11 becomes worse due to the possibility ofunnecessary peeling-off or coming-off of the transfer layer 3 or 13.When the peel strength exceeds 30 g/25 mm, a cohesive failure of thetransfer layer 3 or 13 is likely to occur upon release of the transferlayer 3 or 13 from the base film 2 or 12. When the transfer layer 3 or13 is released from the base film 2 or 12 using a machine, large loadshould be applied on the machine so as to release the transfer layer 3or 13 from the base film 2 or 12 stably at such high peeling strength.

[0240] When the transfer layer 13 with respect to the protective film 14is below 0.1 g/25 mm, on the other hand, the handleability of thetransfer sheet 11 becomes worse because of the possibility ofunnecessary peeling-off or coming-off of the protective film 14. Whenthe peel strength is greater than 30 g/ 25 mm, a cohesive failure of thetransfer layer 13 is likely to occur upon release of the protective film14 from the transfer layer 13. When the protective film 14 is releasedfrom the transfer layer 13 using a machine, it is difficult to provide astable release of the protective film 14 from the transfer layer 13 dueto large tension variations. Preferably, the peel strength of thetransfer layer 13 with respect to the protective film 14 should be lowerthan the peel strength of the transfer layer 13 from the base film 12 byat least 1.0 g/25 mm.

[0241] With the transfer sheet 1 or 11 of the invention, the transferlayer 3 or 13 can be released from the base film 2 or 12 with nocohesive failure of the transfer layer 3 or 13. With the transfer sheet11 having the protective film 14 placed on the transfer layer 13, theprotective film 14 can be released from the transfer layer 13 with norelease of the transfer layer 13 from the base film 12, and no cohesivefailure of the transfer layer 13.

[0242] It is to be noted that the peel strength referred to herein is avalue as measured upon peeling off a sample of 25 mm in width through180° at a speed of 100 mm/min., using a large universal testing machineof the quartz oscillation digital servo constant-speed distortion type,UTM-500.

[0243] On the premise that the fifth transfer sheet of the invention isused primarily for electrode pattern formation, the structures of thebase film, transfer layer, and protective film therein may be the sameas explained in conjunction with the first transfer sheet of theinvention. The peel strength of the transfer layer 3 or 13 with respectto the base film 2 or 12 can be regulated within the above range of 0.2to 30 g/25 mm depending on the content of the inorganic component in thetransfer layer 3 or 13, the type and content of the organic componenttherein, the solvent used, and the coating conditions applied and/or thematerial, thickness, surface state, and heat treatment of the base film2 or 12.

[0244] The peel strength of the transfer layer 13 with respect to theprotective film 14, too, can be regulated within the above range of 0.1g/25 mm to less than 30 g/25 mm depending on the content of theinorganic component in the transfer layer 13, the type and content ofthe organic component therein, the solvent used, and the coatingconditions applied and/or the material and surface state of theprotective film 14.

[0245] In particular, the content of the thermoplastic or photosensitiveresin composition in the transfer layer 3 or 13 may be determined insuch a way that the peel strength between the base film and the transferlayer is in the range of 0.2 g/25 mm to 30 g/25 mm inclusive and thepeel strength between the protective film and the transfer layer is inthe range of 0.1 g/25 mm and 30 g/25 mm inclusive, while the type of theresin material used, the material and surface nature of the base film,and the material and surface nature of the protective film to bedescribed later are taken into consideration. For instance, the resincomposition may be used in an amount of 3 to 50 parts by weight, andpreferably 5 to 40 parts by weight per 100 parts by weight of the aboveinorganic component. When the content of the thermoplastic orphotosensitive resin composition is below 3 parts by weight, the shaperetentivity of the transfer layer 3 or 13 becomes low, and a problemarises especially when the transfer sheet is stored and handled in arolled-up state. In addition, when the transfer sheet 1 or 11 is slit toany desired shape, the inorganic component manifests itself in dustform, which has in turn an adverse influence on the fabrication ofplasma display panels. When the content of the thermoplastic orphotosensitive resin composition exceeds 50 parts by weight, on theother hand, it is impossible to achieve complete removal of the organiccomponent by firing. Consequently, the quality of the electrode patternobtained upon firing drops because carbides remain therein.

[0246] The protective film 14 that forms the fifth transfer sheet of theinvention may be made up of a material that has such surface propertiesas to allow its peel strength with respect to the transfer layer 13 tobe in the range of 0.1 g/25 mm to less than 30 g/25 mm, and is flexibleand less susceptible to large deformation under tension or pressure.

[0247] Reference is made to how to form a PDP electrode pattern, usingthe fifth transfer sheet of the invention.

[0248]FIG. 7 is a process sequence of how to form a pattern form theaddress electrode 74 in the PDP back panel plate 71 using the fifthtransfer sheet 1 of the invention, as in the case of the third transfersheet of the invention. It is here to be noted that the transfer layer 3in the transfer sheet 1 contains a negative photosensitive resincomposition as the organic component removable of firing.

[0249] Referring to FIG. 7, the transfer sheet 1 is pressed on itstransfer layer 3 side against a back glass substrate 72 comprising aprimer layer 73 after which the base film 2 is released from thetransfer sheet 1 for transfer of the transfer layer 3 (FIG. 7(A)). Atthis transfer step, the transfer layer 3 can be well transferred on theglass substrate with no cohesive failure of the transfer layer 3 becausethe peel strength between the base film 2 and the transfer layer 3 is inthe range of 1.0 to 10 g/25 mm. It is here to be noted that when heatingis needed for transfer of the transfer layer 3, the back glass substrate72 may be heated independently or using a pressing roll.

[0250] Then, the transfer layer 3 is exposed to light via a photomask M(FIG. 7(B)). It is here to be noted that when a light-transmitting filmis used as the base film 2, it may be exposed to light before release ofthe base film 2 therefrom.

[0251] Subsequently, the transfer layer 3 is developed, thereby forminga pattern 3′ comprising a conductive photosensitive resin layer on theprimer layer 73 (FIG. 7(C)). Finally, the pattern 3′ is fired to removethe organic component therefrom, thereby forming the address electrodepattern 74 (FIG. 7(D)).

[0252] In the above embodiment, such a transfer sheet of the inventionas shown in FIG. 1 is used. However, it is to be understood that whenthe transfer sheet 11 having the protective film 14 thereon such as oneshown in FIG. 2 is used, the electrode pattern may be formed in the sameoperation as in FIG. 7 after release and removal of the protective film14. The protective film 14 can be well released from the transfer layer13 with no cohesive failure of the transfer layer 13 and with thetransfer layer 13 remaining fixed to the base film 12, because the peelstrength between the protective film 14 and the transfer layer 13 is inthe range of 0.2 to 10 g/25 mm and is lower than that between the basefilm 12 and the transfer layer 13.

[0253] The fifth transfer sheet of the invention is now explained morespecifically with reference to Example 7.

EXAMPLE 7

[0254] A photosensitive resin composition A comprising the followingcomponents was prepared for an ink composition. Composition of thePhotosensitive Resin Composition A Silver powders (in a spherical formhaving an 96 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  4 parts by weight of Bi₂O₃,SiO₂ and B₂O₃ and having a softening point of 500° C. and a coefficientof thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 14 parts by weight methacrylicacid copolymer (with 5 mol % of glycidyl methacrylate added thereto, andhaving a molecular weight of 70,000 and an acid number of 110 mg KOH/g)Pentaerythritol tri/tetraacrylate 11 parts by weight (M-305, ToaSynthesis) Photopolymerization initiator (Irgacure 369, Ciba-  1 part byweight Geigy) 3-Methoxybutyl acetate 20 parts by weight

[0255] Then, the above photosensitive resin composition was coated by ablade coating process on a polyethylene terephthalate film (T-60, TorayIndustries, Inc.) provided as the base film, and dried at 100° C. for 2minutes to form a transfer layer of 17 μm in thickness.

[0256] Next, a protective film or a silicone-treated polyethyleneterephthalate film (SP-PET-03-25-C, Tosero Co., Ltd.) of 25 μm inthickness was laminated on the transfer layer to form such a transfersheet (sample 1) as shown in FIG. 2.

[0257] Photosensitive resin compositions B to E consisting of suchcomponents as mentioned below were used to make transfer sheets (samples2 to 5) in the same manner as mentioned above. It is here to be notedthat sample 5 (composition E) is the same in composition as sample 2(composition B) with the exception that a corona-treated PET film(E5101, Toyobo Co., Ltd.) of 25 μm in thickness was used for the basefilm and an oriented polypropylene film (E-600, Oji Paper Co., Ltd.) of25 μm in thickness was used for the protective film. Composition of thePhotosensitive Resin Composition B Silver powders (in a spherical formhaving an 96 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  4 parts by weight of Bi₂O₃,SiO₂ and B₂O₃ and having a softening point of 500° C. and a coefficientof thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 14 parts by weight methacrylicacid copolymer (having a molecular weight of 70,000 and an acid numberof 140 mg KOH/g) Pentaerythritol tri/tetraacrylate 12 parts by weight(M-305, Toa Gosei) Dibutyl phthalate  2 parts by weightPhotopolymerization initiator (Irgacure 369,  1 part by weightCiba-Geigy) 3-Methoxybutyl acetate 20 parts by weight Composition of thePhotosensitive Resin Composition C Silver powders (in a spherical formhaving an 96 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  4 parts by weight of Bi₂O₃,SiO₂ and B₂O₃ and having a softening point of 500° C. and a coefficientof thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 14 parts by weight methacrylicacid copolymer (having a molecular weight of 70,000 and an acid numberof 140 mg KOH/g) Pentaerythritol tri/tetraacrylate  8 parts by weight(M-305, Toa Gosei) Photopolymerization initiator (Irgacure 369,  1 partby weight Ciba-Geigy) 3-Methoxybutyl acetate 20 parts by weightComposition of the Photosensitive Resin Composition D Silver powders (ina spherical form having an 96 parts by weight average particle size of 1μm) Glass frits (of the non-alkali type composed mainly  4 parts byweight of Bi₂O₃, SiO₂ and B₂O₃ and having a softening point of 500° C.and a coefficient of thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 14 parts by weight methacrylicacid copolymer (having a molecular weight of 70,000 and an acid numberof 140 mg KOH/g) Pentaerythritol tri/tetraacrylate  8 parts by weight(M-305, Toa Gosei) Photopolymerization initiator (Irgacure 369,  1 partby weight Ciba-Geigy) N-methyl-2-pyrrolidone 20 parts by weightComposition of the Photosensitive Resin Composition E Silver powders (ina spherical form having an 96 parts by weight average particle size of 1μm) Glass frits (of the non-alkali type composed mainly  4 parts byweight of Bi₂O₃, SiO₂ and B₂O₃ and having a softening point of 500° C.and a coefficient of thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 14 parts by weight methacrylicacid copolymer (having a molecular weight of 70,000 and an acid numberof 140 mg KOH/g) Pentaerythritol tri/tetraacrylate 14 parts by weight(M-305, Toa Gosei) Photopolymerization initiator (Irgacure 369,  1 partby weight Ciba-Geigy) 3-Methoxybutyl acetate 20 parts by weight

[0258] Then, each of the above transfer sheets (samples 1 to 5) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 7 days. Regarding each of the transfer sheets (samples 1 to 5),the peel strength between the base film and the transfer layer, and thepeel strength between the protective film and the transfer layer weremeasured under the following conditions. The results are reported inTable 7.

Conditions for Measurement of Peel Strength

[0259] A sample of 25 mm in width was cut out of each transfer sheet inits flow direction, and then peeled through 180° at a speed of 100mm/min., using a large Tensiron universal testing machine UTM-500,Oritentic Co., Ltd. to measure its peeling strength.

[0260] After the above storage, the protective film was then releasedfrom the transfer sheet, which was in turn pressed against a glasssubstrate at room temperature, using an auto-cutting laminator having aroll heated to 40° C. Following this, the glass substrate was cooleddown to room temperature to transfer the transfer layer on the glasssubstrate after release of the base film therefrom. At this transferstep, the releasability of the protective film from each of the transfersheets (samples 1 to 5), and the transferability of the transfer layertherefrom (including the transferability of the base film) wereobserved. The results are reported in Table 7.

[0261] Then, the transfer layer was exposed to ultraviolet radiation of800 mJ/cm² (from a light source, i.e., a super high-pressuremercury-vapor lamp) via a negative pattern mask (with an opening linewidth of 70 μm) for plasma display panel electrodes. Following this, thetransfer layer was developed with a 0.5% aqueous solution of sodiumcarbonate, washed with pure water, and dried to obtain a given pattern.Then, the glass substrate was fired at 600° C. to form an electrodepattern.

[0262] The thicknesses and line widths, as measured, of the thus formedelectrode patterns are shown in Table 7. TABLE 7 Peel Strength (g/25 mm)Base vs. Protection vs. Releasability Transfer- Thickness of Line Widthof Transfer Sheet Transfer Layer Transfer Layer Protective Film abilityElectrode Pattern Electrode Pattern Sample 1 3.0 1.0 good good 17 ± 1 (7± 1) μm* 71 ± 3 (60 ± 3) μm* Sample 2 5.0 2.5 good good 17 ± 1 (7 ± 1)μm* 71 ± 3 (60 ± 3) μm* Sample 3 2.0 0.5 good good 17 ± 1 (7 ± 1) μm* 71± 3 (60 ± 3) μm* Sample 4 ≦0.2 ≦0.1 (1) (2) many breaks found Sample 536 32 (3) (4) many breaks found

[0263] From Table 7, it is found that each of the fifth transfer sheets(samples 1 to 3) of the invention is improved in terms of thereleasability of the protective film from the transfer layer, and thetransferability of the transfer layer to the glass substrate as well. Itis also found that the patterns obtained using these transfer sheetshave uniform thicknesses and line widths, and are formed with highaccuracy.

[0264] In one comparative transfer sheet (sample 4) wherein the peelstrength between the base film and the transfer layer is below 0.2 g/25mm and the peel strength between the protective film and the transferlayer is below 0.1 g/25 mm, on the other hand, air and foreign matterare trapped between the protective film and the transfer layer uponslitting. It is also found that the transfer layer is susceptible topeeling or cracking because the adhesive force between the base film andthe transfer layer is weak. In the electrode pattern formed using thistransfer sheet, therefore, many breaks are found.

[0265] In another comparative transfer sheet (sample 5) wherein the peelstrength between the base film and the transfer layer is greater than 30g/25 mm and the peel strength between the protective film and thetransfer layer is greater than 30 g/25 mm, the transfer layer is injuredor dented upon release of the protective film therefrom, and undergoes alocal cohesive failure upon release of the base film therefrom. In theelectrode pattern formed using this transfer sheet, therefore, manybreaks are found.

[0266] Reference is now made to the sixth transfer sheet of theinvention. Like the first transfer sheet of the invention, the sixthtransfer sheet of the invention is a transfer sheet capable of forming,with high accuracy, fine patterns such as electrodes, resistorsinclusive of dielectric layers, and barriers for use with image displayequipment inclusive of PDPs and liquid crystal display devices, thermalheads, and integrated circuits.

[0267] Referring to FIG. 1, the transfer layer 3 is releasably providedon the base film 2. This transfer layer 3 comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and has a residual solvent content of at most 100mg/m², preferably at most 50 mg/m², and more preferably at most 30mg/m².

[0268] Referring to FIG. 2, the transfer sheet 11 comprises a base film12, a transfer layer 13 releasably provided on the base film 12, and aprotective film 14 releasably provided on the transfer layer 13. Thistransfer layer 3 comprises, at least, an inorganic component including aglass frit and an organic component removable by firing, and has aresidual solvent content of at most 100 mg/m², preferably at most 50mg/m², and more preferably at most 30 mg/m².

[0269] In the present invention, it is not preferable that the transferlayer 3 or 13 has a residual solvent content of greater than 100 mg/m²,because the transfer layer 3 or 13 is susceptible to a cohesive failureupon release of the base film 2 or 12, or the protective film 14therefrom. This is also not preferable because the adhesive forcebetween the transfer layer 3 or 13 and the base film 2 or 12 or theprotective film 14 becomes too high, resulting in a releasability dropand a lowering of the storage stability of the transfer sheet 1 or 11,and because when a photosensitive resin composition is used as theorganic component removable by firing, patterning accuracy drops uponexposure, and development.

[0270] The structures of the base film, transfer layer, and protectivefilm in the sixth transfer sheet of the invention may be the same asexplained in conjunction with the first transfer sheet of the invention.

[0271] Reference is then made to how to form a PDP electrode pattern anda dielectric layer using the sixth transfer sheet of the invention.

[0272]FIG. 7 is a process sequence of how to form a pattern form theaddress electrode 74 in the PDP back panel plate 71, using the sixthtransfer sheet of the invention. It is here to be noted that thetransfer layer 3 in the transfer sheet 1 contains a negativephotosensitive resin composition as the organic component removable byfiring.

[0273] Referring to FIG. 7, the transfer sheet 1 is pressed on itstransfer layer 3 side against a back glass substrate 72 provided with aprimer layer 73, after which the base film 2 is released from thetransfer sheet 1 for transfer of the transfer layer 3 (FIG. 7(A)). It ishere to be noted that when heating is needed for transfer of thetransfer layer 3, the back glass substrate 72 may be heatedindependently or using a pressing roll.

[0274] Then, the transfer layer 3 is exposed to light via a photomask M(FIG. 7(B)). It is here to be noted that when a light-transmitting filmis used as the base film 2, it may be exposed to light before release ofthe base film 2 therefrom.

[0275] Subsequently, the transfer layer 3 is developed, thereby forminga pattern 3′ comprising a conductive photosensitive resin layer on theprimer layer 73 (FIG. 7(C)). Finally, the pattern 3′ is fired to removethe organic component therefrom, thereby forming the address electrodepattern 74 (FIG. 7(D)).

[0276] In the above embodiment, such a transfer sheet of the inventionas shown in FIG. 1 is used. However, it is to be understood that whenthe transfer sheet having the protective film thereon such as one shownin FIG. 2 is used, the pattern may be formed in the same operation as inFIG. 7 after release and removal of the protective film 14. In thisregard, it is to be understood that when the dielectric layer 75 isprovided in a full-solid form, the organic component can be removed byfiring immediately after transfer of the transfer layer.

[0277] The sixth transfer sheet of the invention is now explained morespecifically with reference to Examples 8, and 9.

EXAMPLE 8

[0278] A conductive photosensitive resin composition consisting of thefollowing components was prepared as an ink composition. Components ofthe Photosensitive Resin Composition Silver powders (in a spherical formhaving an 96 parts by weight average particle size of 1 μm) Glass frits(of the non-alkali type composed mainly  4 parts by weight of Bi₂O₃,SiO₂ and B₂O₃ and having a softening point of 500° C. and a coefficientof thermal expansion α₃₀₀ of 80 × 10⁻⁷/° C.) n-Butylmethacrylate/2-hydroxyethyl methacrylate/ 13 parts by weight methacrylicacid copolymer (having a molecular weight of 70,000 and an acid numberof 140 mg KOH/g) Ethylene oxide-modified trimethylolpropane 11 parts byweight triacrylate (M-350, Toa synthesis) Photopolymerization initiator(Irgacure 369,  1 part by weight Ciba-Geigy) 3-Methoxybutyl acetate 20parts by weight

[0279] Then, the above ink composition was coated by a blade coatingprocess on a 50 μm thick polyethylene terephthalate film (T-60, TorayIndustries, Inc.) provided as the base film, and dried at 100° C. for 2minutes to form a transfer layer of 17 μm in thickness. The transferlayer had a residual solvent content of 30 mg/m².

[0280] Next, a protective film or a polyethylene film (GF-3, TamapolyCo., Ltd.) of 90 μm in thickness was laminated on the transfer layer toform such a transfer sheet (sample 1) as shown in FIG. 2.

[0281] Transfer sheets (samples 2 to 6) were prepared as in the samemanner as in sample 1 with the exception that the drying conditions werevaried to regulate the residual solvent content of the transfer layer to5 mg/M², 50 mg/m², 100 mg/m², 150 mg/m², and 300 mg/M².

[0282] Then, each of the above transfer sheets (samples 1 to 6) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 7 days. Thereafter, the protective film was released from thetransfer sheet, which was in turn pressed against a glass substrateheated to 80° C., using an auto-cutting laminator having a roll heatedto 40° C. Following this, the glass substrate was cooled down to roomtemperature to transfer the transfer layer to the glass substrate afterrelease of the base film therefrom.

[0283] Then, the transfer layer was exposed to ultraviolet radiation of700 mJ/cm² (from a light source, i.e., a super high-pressuremercury-vapor lamp) via a negative pattern mask (with an opening linewidth of 70 μm) for plasma display panel electrodes. Following this, thetransfer layer was developed with a 0.5% aqueous solution of sodiumcarbonate to obtain a given pattern. Finally, the glass substrate wasfired at 600° C. to form an electrode pattern.

[0284] The thicknesses and line widths, as measured, of the thus formedelectrode patterns are shown in Table 8. TABLE 8 Thickness of Line Widthof Transfer Residual Solvent Electrode Electrode Sheet Content (mg/m²)Pattern (μm) Pattern (μm) Sample 1 30 6 ± 1 60 ± 3 Sample 2 5 6 ± 1 60 ±3 Sample 3 50 6 ± 1 60 ± 3 Sample 4 100 6 ± 1 60 ± 3 Sample 5 150 4 to 9*1 60 ± 8 *1 Sample 6 300 — *2 — *2

[0285] From Table 8, it is found that the electrode patterns obtainedusing the transfer sheets (samples 1 to 4) of the invention have uniformthicknesses and line widths and are formed with high accuracy. It isalso found that the transfer sheets have high storage stability.

[0286] In each of the transfer sheets (samples 5, and 6) having anincreased residual solvent content, it is found that the pattern flows,resulting in the occurrence of many chips and breaks. It is also foundthat these transfer sheets have poor storage stability due to theseeping of the transfer layers from their sides, the cracking of thetransfer layers, the peeling-off of the protective films, and thecohesive failures of the transfer layers upon release of the base film,etc.

EXAMPLE 9

[0287] An ink composition consisting of the following components wasprepared for dielectric formation. Component of the Ink CompositionGlass frits (of the non-alkali type composed mainly 70 parts by weightof Bi₂O₃, SiO₂ and B₂O₃ and having an average particle size of 3 μm)TiO2  7 parts by weight AlO₃  5 parts by weight

[0288] It is here to be noted that the above inorganic component mixturehad a softening point of 570° C., a glass transition temperature Tg of485° C. and a coefficient of thermal expansion a300 of 80×10⁻⁷/° C.n-Butyl methacrylate/2-hydroxyethyl methacrylate/ 20 parts by weightmethacrylic acid copolymer (at a molar ratio of 8/2 and having amolecular weight of 300,000) Adipate type transferability-impartingagent 12 parts by weight (Adecaizer RS107, Asahi Denka Kogyo Co., Ltd.)Propylene glycol monomethyl ether 50 parts by weight

[0289] Then, the above ink composition was coated by a blade coatingprocess on a 25 μm thick polyethylene terephthalate film (T-60, TorayIndustries, Inc.) provided as the base film, and dried at 100 ° C. for 2minutes to form a transfer layer of 25 μm in thickness. The transferlayer had a residual solvent content of 20 mg/m².

[0290] Next, a protective film or a silicone-treated polyethylene film(SP-PET-03-25-C, Tosero Co., Ltd.) of 25 μm in thickness was laminatedon the transfer layer to form such a transfer sheet (sample 1) as shownin FIG. 2.

[0291] Transfer sheets (samples 2 to 4) were prepared as in the samemanner as in sample 1 with the exception that the drying conditions werevaried to regulate the residual solvent content of the transfer layer to40 mg/m², 80 mg/m², and 150 mg/m².

[0292] Then, each of the above transfer sheets (samples 1 to 4) was slitto a given width, and rolled around an ABS resin core for storage at 25°C. for 7 days. Thereafter, the protective film was then released fromthe transfer sheet, which was in turn pressed against a glass substrate(with an electrode pattern already formed thereon) heated to 100° C.,using an auto-cutting laminator having a roll heated to 100° C.Following this, the glass substrate was cooled down to room temperatureto transfer the transfer layer to the glass substrate after release ofthe base film therefrom.

[0293] Finally, the glass substrate was fired at 570° C. to form adielectric layer.

[0294] The thicknesses and line widths, as measured, of the thus formeddielectric layers are shown in Table 9. TABLE 9 Thickness of TransferResidual Solvent Dielectric Layer Sur. States of Sheet Content (mg/m²)(μm) Dielectric Layer Sample 1 20 10 ± 1 good Sample 2 40 10 ± 1 goodSample 3 80 10 ± 1 good Sample 4 150 7 to 13 pinholes found

[0295] From Table 9, it is found that the dielectric layers obtainedusing the transfer sheets (samples 1 to 3) of the invention have uniformthicknesses, and satisfactory surface flatness as well. It is also foundthat the transfer sheets have high storage stability.

[0296] On the other hand, the dielectric layer obtained using thetransfer sheet (sample 4) having an increased residual solvent contentis found to have many pinholes, and an unsatisfactory thicknessdistribution as well. Also, the storage stability of this transfer sheetis unsatisfactory due to the seeping of the transfer layer from itsside, the cohesive failure of the transfer layer upon release of thebase film.

What we claim is:
 1. A transfer sheet comprising, at least, a base filmand a transfer layer releasably provided on the base film, characterizedin that said transfer layer comprises, at least, an inorganic componentincluding a glass frit and an organic component removable by firing, andhas a surface roughness Ra of at most 0.4 μm.
 2. The transfer sheetaccording to claim 1, characterized in that said transfer layer has aprotective film releasably provided thereon, said transfer layer showinga surface roughness Ra of at most 0.2 μm upon release of said protectivefilm therefrom.
 3. The transfer sheet according to claim 1 or 2,characterized in that said organic component is sensitive to light. 4.The transfer sheet according to any one of claims 1 to 3, characterizedin that said transfer layer contains an electrically conductive powderas said inorganic component.
 5. A transfer sheet comprising, at least, abase film and a transfer layer releasably provided on said base film,characterized in that said transfer layer comprises, at least, aninorganic component including a glass frit and an organic componentremovable by firing, and has a surface gloss of 20 to 110 inclusive. 6.The transfer sheet according to claim 5, characterized in that saidtransfer layer has a protective film releasably provided thereon, saidtransfer layer showing a surface gloss of 30 to 110 inclusive uponrelease of said protective film therefrom.
 7. The transfer sheetaccording to claim 5 or 6, characterized in that said organic componentis sensitive to light.
 8. A transfer sheet comprising, at least, a basefilm and a transfer layer releasably provided on said base film,characterized in that said transfer layer comprises, at least, aninorganic component including a glass frit and an electricallyconductive powder and an organic component removable by firing, and hasa surface gloss of 20 to 110 inclusive.
 9. The transfer sheet accordingto claim 8, characterized in that said transfer layer has a protectivefilm releasably provided thereon, said transfer layer showing a surfacegloss of 40 to 110 inclusive upon release of said protective filmtherefrom.
 10. The transfer sheet according to claim 8 or 9,characterized in that said organic component is sensitive to light. 11.A transfer sheet comprising, at least, a base film and a transfer layerreleasably provided on said base film, characterized in that saidtransfer layer comprises, at least, an inorganic component including aglass frit and an organic component removable by firing, and a peelstrength between said base film and said transfer layer ranges from 2g/25 mm to 30 g/25 mm inclusive.
 12. The transfer sheet according toclaim 11, characterized in that said transfer layer has a protectivefilm releasably provided thereon, and a peel strength between saidprotective film and said transfer layer ranges 1 g/25 mm to 27 g/25 mminclusive and is lower than said peel strength between said base filmand said transfer layer.
 13. The transfer sheet according to claim 11 or12, characterized in that said organic component is sensitive to light.14. A transfer sheet comprising, at least, a base film and a transferlayer releasably provided on said base film, characterized in that saidtransfer layer comprises, at least, an inorganic component including aglass frit and an electrically conductive powder and an organiccomponent removable by firing, and a peel strength between said basefilm and said transfer layer ranges from 0.2 g/25 mm to 35 g/25 mminclusive.
 15. The transfer sheet according to claim 14, characterizedin that said transfer layer has a protective film releasably providedthereon, and a peel strength between said protective film and saidtransfer layer ranges 0.1 g/25 mm to less than 30 g/25 mm and is lowerthan said peel strength between said base film and said transfer layer.16. The transfer sheet according to claim 14 or 15, characterized inthat said organic component is sensitive to light.
 17. A transfer sheetcomprising, at least, a base film and a transfer layer releasablyprovided on said base film, characterized in that said transfer layercomprises, at least, an inorganic component including a glass frit andan organic component removable by firing, and has a residual solventcontent of at most 100 mg/m².
 18. The transfer sheet according to claim17, characterized in that said transfer layer has a protective filmreleasably provided thereon.
 19. The transfer sheet according to claim17 or 18, characterized in that said organic component is sensitive tolight.
 20. The transfer sheet according to any one of claims 17 to 19,characterized in that said transfer layer contains an electricallyconductive powder as said inorganic component.
 21. A plasma displaypanel characterized by being fabricated using a transfer sheet asrecited in any one of claims 1 to 20.